I think both your idea and the status quo have their benefits.
If you think about it, choosing gear AFTER seeing the enemy team allows for strategic and specialized gear loadouts, which allows to solve specific problems, as you described.
However, selecting gear BEFORE this point encourages more generalistic loadouts, that match your general playstyle, regardless of enemy or situation.
As gear is already a choice between buffing your character’s strengths or adressing some of it’s weak spots, I’m not sure if we need to abstract this another level.
To that end, I’ll have to admit that I don’t know whether most people favor Offensive or Defensive Gear Loadouts - especially in PvP.
In Story Missions, I mostly went with defensive loadouts, maybe one offensive Gear Piece.
A dead BB does no damage 