Ok, I gave it some extra thought and realized that most Jedi already have leadership skills. There's a lot available to choose from. Since Plo had two special abilities before, it might be prudent to simply remove his earlier, useless leadership skill and go back to two special abilities instead. So here's my suggestion.
Plo Koon revamped
http://static.comicvine.com/uploads/original/11113/111137054/3820179-star+wars+-+clone+wars+adventures+volume+6-074.jpg
Ability 2, Form V - Deal physical damage to one opponent and lock their abilities for (x) turns. If the opponent's physical damage power is higher than Plo Koon's own, Plo Koon also deals (%) of that difference in extra damage, and gains Retaliation for (x) turns.
This second ability would give Plo Koon a broader palette and make him more useful right from the start of a battle, whereas Electric Judgment might be better to save for any buffs the opponent may gain, and Plo's basic attack only really becomes damaging once the battle has gone on for some time. This second ability can be used straight off the bat, but stays true to the concept of the character, that he becomes stronger against heavy attackers. Retaliation fits perfectly with Form V and also makes it a little more costly for enemy teams to take out Plo Koon early.
I'll update my original post with this new suggestion.