I think it's entirely fair for Bungo to dedicate a season to Gambit. Fresh new game mode coming out of Forsaken with a lot of potential but needed some overhauls. As a result, I think it's in a good place right now. Not entirely perfect but such is the endless cycle of Destiny.
That said, it came at the sacrifice of meaningful PVE content to sink our teeth into. And personally, that's mostly the stuff I'm into. I can play Crucible and Gambit and enjoy it because I'm fucking good at it what can I say I make milk out of clay, but it's not what keeps me coming back. Point being, I'm not against a season being dedicated to Gambit, but it comes at a cost. All the eggs in one basket, you know.
At the very least, each season needs a Shattered Throne-esque dungeon. Maybe that's asking for too much, I don't know, I don't make games. But it's content everyone can get in on. Not as big as a raid, but not as meh as forges or Reckoning.