Red eyes fusion & Neos fusion should be limited to 1.
The concept of fusion summon using monsters in your deck is just too broken. That is more like a pot of greed for deck thinning purpose.
Being able to thin your cards down isn't everything. Dark World, Exodia, self-mill, etc. None of those are top-tier strategies. It's not about how many cards you draw. It's what you can do "with" said cards.