So, I just got done playing Yip Yap and playing against him and I have to say he's fun and an innovative play style and character, but I think 343i might ned to take a second look at him because of a certain issue with his unit play style. The issue is similar to Colony's leader unit being too powerful, the same can be said with Yip Yap's Goblin Mechs as his "Don't Shoot Me" power, plus Mechs makes them almost too powerful. I say this because all throughout a few matches people using Yip Yap used this method and even with significant amount of time to rally counter strategies, they all failed, because not only are the Goblin Mechs extremely tanky with a lot of shield and health, they also have too much damage power as well, combined with locusts and the "Don't Shoot Me" power, they instantly annihilate bases and defenses. So I don't want to outright say he should be nerfed, but maybe implementing other counter measures like increasing other leaders strategy effectiveness might be enough to level the playing field.
Yip Yap needs a second look.