Gambit they didn't want to exploit that character. Cyclops has one of the most boring movesets around and the Vs. series loses nothing by losing him.
In truth, most people want both cause they're fixated on the 90s X-men series and/or the previous vs. games, and can't seem to look past what's actually good decision making and what's random fan-wank that the majority of people do not care about. Notice how people think Jin, CapCom and Strider Define the MvC Series, and must be in the game, even though most people don't have a clue who any of those 3 are.
(this is not directed at you necessarily, Rob, just there are lots of idiots like this.)
The polls are generally bad indicators, at least on the Marvel side, for the most part, cause most of them are people who don't know anything about Marvel outside of the two samples I noted. You're a rare case of someone who likes Gambit, for example, and does NOT fall under either "knowledge of Marvel stems from X-men 90s Cartoon!" or "the MvC series" (this is not meant to be an insult)