I am not arguing the merits of whether Gallagher deserves the C over Weber, based on both their Habs careers, Gallagher obviously has that advantage. I think Weber has been good while a Hab but the number of games alone gives Gallagher that edge. He has been a Hab much longer, he does play his ass off every night, no debate there, and he deserves a ton of respect for that.
However, provided Weber is staying here long term, I see him as the only choice from management. They made the drastic trade of Weber/Subban with leadership firmly as part of their decision. There is no way they would pick anyone else but Weber, it would be an indictment on their trade decision to have anyone else be their captain.
If its a players vote, again this goes to Weber. His persona and reputation may be bigger than his game right now but in the room I am willing to bet everyone defers to him. It would be a landslide victory for him.
The only way I see Gallagher being named captain over Weber is if they commit publicly to the rebuild with the intent of trading Weber as part of that rebuild..