Anything with anti-Jedi skills will be viable long-term, like Dooku. Droids would be another group - HK for example. You also have to take in to account if you're talking about Dooku in a D slot or Dooku being used by a human not playing on auto. Sure Dooku has lower health, but the enemy AI really doesn't try to expose that. So many are running Jedi now - and I can't ever see this SW game not featuring Jedi prominently as we have no shortage of more strong Jedi yet to be released - Dooku is a great tool. He leads off matches with a high stun chance vs. Jedi - great tactical tool to use vs. Jedi. His ability block / stun chance on basic vs Jedi is valuable too when trying to prevent all the great Jedi specials from firing while you damage down a target...Ben, Barriss, Lumi, etc. with their specials.
Also, on him being a slow farm - maybe compared to Lumi yes, but tomorrow will be 3 weeks of playing for me. I have Dooku for example at 40/65 to 5*. So I've farmed 70 Dooku Shards in 3 weeks. He needs 110 more shards to get to 6* for example - that's a little less than 5 weeks form now and he will be 6* - should be 5* in a week or so. I don't think that's so bad.
Want to make a comment on "end game" as well....really no one knows the end game because we are capped at 60 currently, but we won't be indefinitely. Levels are capped, but more importantly specials, gears, and leader abilities are currently blocked as well with the level cap. Let's take Darth Maul as an example. His Dancing Shadows leader provides him with evade and turn meter - his two big weaknesses are health and slow speed. Well as his evade % and meter % from evading scales up, this will help address his two biggest holes as a toon. Those are all blocked though due to 60 cap. So no one for sure knows how Maul plays out when he's fully built. While you could say, well everyone else will be built too so it evens out...that's not necessarily the case. Maul's leader skill specifically covers up a weakness of his - health / speed. Other leader skills do not really cover up a weakness. Barriss for example just has a leader that gets more and more tanky. As her leader scales up, you just get more and more health / tankiness; her skill just accentuates her current strengths. If as it scaled she gained damage that'd be filling a weakness like Maul. Maybe the scale on Maul ends up not being good enough to overcome his deficiencies, but you can't know for sure. This doesn't even take in to account new toons released over time and how that can shift meta.
Lastly - just play the game more before you say anything is OP. I'd say Old Ben is way more tactically challenging than Dooku by a mile - at first I just couldn't see how he could be countered and thought he was OP, but after fighting him so much he's now pretty manageable once you build teams that can counter him and his healing Jedi units. You start to build a pattern and understand when to fire a special, timing to pull an ability block, when to attack and damage down a specific unit. Takes time to learn nuances of a battle and certain opponents. When their specials fire, etc. We are only 3 weeks in - wait to judge units until you have a good chunk of the roster to work with. Nerfing Dooku would be silly because he's not even close to the toughest toon to manage. I'd say even like HK47 is tougher to handle for me than Dooku. His aoe special just splatters all over my Jedi team and I'm dealing with ability block, damage down, and speed down...and he has a cooldown of just 2 on that move :) Can seriously weaken my entire team. Dooku just hits one toon mostly.
