Nerfs:
Eggy is below average (for a bossfight) at melee combat and such, this is the reason has a Trident, a weapon with more reach and the ability to be thrown easily.
Eggys shell is weaker now, it's about as strong as Galactic Gold.
Eggy isn't a master at Egg magic, he's very good at it, but he's not the best.
Plus something that's already been canon:
Eggy is somewhat dumb when it comes to social skills and reasoning. He doesn't pick up on many tricks or jokes, especially dirty jokes considering he's also pretty innocent. He can be baited in a battle without too much trouble (although you might have trouble taking him down despite that).
Caption this Meme 