>>96159864
The cascade/discover/mill cards and play them for free subtheme is simply there to double dip on value when it comes to casting Cascade creatures. Due to how the deck is built, more than 70% of the time I will be cascading into a two land ramp spell that I cast for free, and if not I cascade into one of my draw engines.
The only reason I would really see cutting it is if the mana ramp it nearly always guarantees doesn't actually give me any kind of value other than having more land on board, which is certainly true in some cases.