Personally, I like choice. Both mods have their own philosophies which differ. Even the target audience is different (NYGM for the more realism focussed, GW for the more broader player).
What you are saying Drebbel is (figuratively speaking) akin to asking Pepsi and Coke to merge. Or Holden and Ford. Or perhaps more accurately Maccas and KFC...etc...etc...
Competition, be it perceived or real, usually results in a better product. And the product is the bottom line. Give me two, three, four products and let me choose the one
(s) I want.