Is AO Deathstroke behind the curve?- My thoughts

Topping off a few of the teams I've previously discussed, Deathstroke is the absolute upper tier Free Agent in terms of cost and statline. As one of the best fighters in the DC Universe, he can reliably take on opponents in combat, although he is very pricey and he is difficult to compare to other generic Free Agents because of just how much he brings.

Offensive
With 3 different ways to attack and 2 weapon profiles, Deathstroke is a pretty good toolkit when it comes to killing.
His Reinforced Bo is a pretty great weapon with rerolls to hit and Reach doing double stun, but with his attack 5 Combo on top he can very easily knock out most things, and can even take multiple henchmen out of the game in a single activation. The consistency in hitting is needed against higher defence models, and it is for that reason I would always use the Bo against them
His other weapon is a simple Sword, doing double blood with Sharp. Not getting Combo here isn't great, but the damage is still very good and should be the weapon of choice against low defence models because it will quite likely outright kill them.
Hidden Sniper is his way of attacking at range, and it is a pretty good one. As previously mentioned with Commissioner Gordon, it is a way of getting unlimited range pingless shooting that is pretty good damage, letting him cover targets he normally wouldn't be able to reach, and as it is a trait he can use his regular attacks against a different target anyway, spreading out his potential damage a very long way.
The last piece of offensive tech Deathstroke has is his Counter Attack, letting him use successful block rolls to hit his opponent back and do some extra damage. It is most often best to use the sword for this as it is blood damage, but it depends on the target. Counter Attack in general isn't something I see as hugely valuable although it is good, as it relies on first hitting defence 5 then you rolling successful blocks before you can make your attacks (that is, it's a lot of hoops to jump through and not that great outside of Bronze Tiger) but if he is defending a position that's important, it can be very useful.
Defensive
Martial Artist and Defence 5 are always amazing, but adding it to the rest of the tricks he has makes Deathstroke a very tough model to remove from the table. Stealth is a little extra protection against guns and synergises very well with his Acrobat, which at movement 3 means he is not likely to be getting shot very often, and when he does he will be dangerously close.
His Soul Armour is a once per game ability that lets him heal 2 damage counters off himself, although at the cost of 3SC to do so it's a hefty investment and must be assessed if it's worth doing. It can be very good, but oftentimes it's just better to hit an opponent that is threatening him or to block.
Overall
Acrobat helps speed him up with +1 to his BMD and some placement tricks, but the more important trait in this regard is Undercover. Being able to not only deploy further up the table, but to drop after most other models, gives him a great degree of flexibility and reactive play to where he goes, letting him choose his game plan a lot better than most FA beaters.

Comparison to other villain FAs- Is Deathstroke overcosted? 
Deathstroke's 145 rep cost may seem to make him an unfavourable choice in comparison to some of the cheaper villain FA options (primarily King Shark, Batman Who Laughs and the Merciless, who I will talk about below) but he does bring a ton of tricks to play that can make this argument a lot more positive in his favour.
King Shark
While King Shark looks very similar in his offence to Deathstroke, both having attack 5 with combo and strength 3+, Deathstroke comes out on top for a variety of reasons that cannot be discounted. Against shooting, Shark is defence 3 with Huge, meaning he will realistically be getting shot a lot more than Deathstroke, and Bulletproof Vest and Regeneration are helpful but ultimately stacking damage on him isn't all that hard. They share the same endurance, but Deathstroke's defence 5, Martial Artist, Stealth and Acrobat giving him a 50% chance of dodging means he is significantly harder to take out in all regards, something which is a huge factor in his 50 rep increase in points.
Movement wise, Shark is 2" faster at his full output, and Amphibious makes sewers a lot cheaper.  But Deathstroke's Undercover and Reach compensate for this, making them overall roughly similar in threat range although Deathstroke's smaller base and Acrobat can help a lot in positioning him on the table.
Talking their weapon profiles they are fairly comparable when you look at the Bo, as Shark trades Reach and Handy for getting blood damage and rolling 2 crit die, which synergises greatly with Brutal to let him fish for what he wants. Shark's Bloodthirsty offsets his first counter loss from damage, and he is tuned up when he is attacking models that have taken damage through Blood Scent getting +1 to hit and wound and crit blood. This puts his potential output higher than Deathstroke, but it needs to be set up and thus isn't as efficient as Deathstroke (and probably needs an investment that is almost as high as Slade anyway). Either one of them will destroy whatever they touch, but Deathstroke is slightly more efficient in doing it, and can do it on the defence as well with Counter Attack if needed.
Batman Who Laughs
This is probably the worst comparison for Deathstroke, but BWL is only 5 rep cheaper and costs more funding. They share an identical statline apart from 1 higher willpower and endurance on BWL, both have ways to heal (Cannibal vs Soul Armour, BWL wins here) and both have great defensive traits (Martial Artist on both, Counter Attack on Deathstroke). Trickster gives BWL insane versatility, and while Deathstroke has Undercover for an increased deployment (and later drop) BWL has Large to increase his movement slightly more over Deathstroke (6" vs 5", Deathstroke will still make combat sooner due to Undercover).
It is where they have ranged protection that they first begin to tip slightly towards Deathstroke, as Protective on BWL is only a 33% chance of passing, while Deathstroke's Dodge (if he has the counters) is a 50% chance of success, making him that little bit more likely to make combat. It is less counter efficient, but Deathstroke having Combo offsets that anyway once he gets to where he wants to be fighting.
Offensively BWL seems slightly better through having Blood/Stun as compared to Deathstroke's Bo and having Luck to possibly reroll wound rolls, but Combo on the Bo means Deathstroke is usually fighting with even more dice thus guaranteeing damage vs lower defence targets and hitting higher potential damage at the same time, making him better against low defence/high endurance models in general. BWL's gun is also strictly inferior to Hidden Sniper most of the time, having worse damage, far less range, allowing Ping! and less native shots. Deathstroke can't use his gun turn 1, but realistically neither can BWL outside of silly play from an opponent and neither of them will likely be attacking until turn 2 anyway
BWL also provides pre-game bonuses and little bits of control through Strategist, Detective and Persuasive, while Deathstroke doubles down on his combat through the not wholly reliable Counter Attack. This is probably more in favour of BWL.
BWL is more versatile in his counters between his higher willpower and Trickster, but Deathstroke is very efficient with what he has, and they are overall fairly comparable in their costs, although Deathstroke should probably be a little lower in relation.
The Merciless
When you're looking at Merciless, it is apparent he is seriously undercosted. His statline is excellent for his role as a beater, and he is very reliably killing most models. Deathstroke is worse here in terms of sheer killing ability sure, but Merciless has a few things that make him a bit more manageable than Deathstroke and that play into Slade's favour. This is absolutely not a favourable comparison for Deathstroke by any means, but in my opinion this is because Merciless needs to be increased in cost if anything, because he is a bad comparison to anything in his cost bracket.
Attack wise Merciless is almost just better. Higher strength and attack, and his sword is better than Deathstroke's by virtue of having +1 to hit and Anti-Tank, and Unstoppable potentially shuts down blocks, but Deathstroke is more counter efficient with Combo and with Reach is able to easier reach models. Hidden Sniper gives a ranged option to Deathstroke, while Merciless has none, making him better in this regard.
Defensively it's a tough competition, as Deathstroke is harder to hit and has Dodge against ranged weapons, while Merciless has a lower defence and Large making him somewhat prone to shooting, although he compensates with Medium Armour. Both have Martial Artist making it a moot point, that's as good as each other, but Merciless does have 1 extra endurance which matters. Soul Armour is clutch, and can keep Deathstroke alive longer, but isn't going to always see play.
Speed wise it's the same as BWL, Large is offset by Undercover.
Deathstroke has the win of being able to claim objectives and score VP though, while Merciless cannot. This is a big point in comparison, as it stunts Merciless in his role while Deathstroke can do a variety of things while he moves around.
Veteran is another in favour of Merciless, as he can move around some counters while Deathstroke just can't.
Overall
For the reasons discussed above, Deathstroke is still largely justifiable for his premium cost, and will do a lot of work in game despite being very expensive. There are absolutely cheaper options that will do one of his roles better, and this allows extra models to fill out the crew, but in the end none of them majorly compare to Deathstroke in the role that he fills, and they will do different jobs that aren't 100% comparable.