Some things worth noting are that EP has really low defense, a flat boost like 50% of RG's defense would be a bit more effective. Also back when RG was meta his taunt lasted two turns despite the description stating it lasted one turn, which was pretty crucial since he gains turn meter after an ally takes damage and a one turn taunt would be lost almost immediately. If he taunted for two turns whenever an Empire ally falls under full health it would help. Overall though this looks great and I would love to see it in-game.
edit: I think the health condition on RG's basic was also added as a nerf, I can't remember, that could also be removed but I think it's interesting as it is