I'm with you about being ok with Gambit as a supporting character with a good arc and fun scenes in a successful MCU version of the X-Men. But man, we have been teased for so long with Gambit by FOX, even well before Tatum was rumored to play him that even that might seem a little disappointing to me.
And I completely disagree with people who say tatum is the wrong choice for Gambit. I honestly believe he was going to really impress a lot of people with his portrayal(assuming there was good material) and was going to look great as him. I was looking forward to what he was going to do with the character.