Dooku adds to the shocks and stuns that prevent the enemy from healing and taking turns. Each enemy with shock means faster TM gain for Palps.
Tarkin can mass reduce turn meter every few turns, so it's the same theme of preventing the enemy from taking turns, but probably not as debilitating for opponents as Dooku.
At this stage, if using Dooku would break up a team, I'd probably leave things how they are.