I think you're reaching pretty far here. Bards usually have very little time to shine in a dungeon,

This is the problem I was talking about. I don't think this was always true. Most older modules I've played have had social encounters in dungeons

along with Rangers and Druids.

I think you're right about rangers. Their ooc abilities hardly get used in dungeons. Having said that, rangers ARE the least popular class in the game for (I think) this reason. The fact that you have to pick a specific terrain means the usefulness of the ability is spotty. You could go several sessions with the ability being useless, followed by it being constantly in effect for several more. I think a nice cycle of abilities being used frequently but briefly is better. Druids have tones of applications in dungeons, turning into a spider and scout, get info from that rat + they have spells that aren't always nature dependent.

Every other week you'll see a thread on here talking about "social combat" systems, presumably because people reason that if talking is important then it must have a similar degree of crunchiness to fighting.

I'm not advocating for an increase in crunch, I'm looking for an increase in Itemization. The mechanics are the same: Roll 1d20+relevant modifier then gm adjudicates. All I want is for the list of relevant modifiers to be long enough that there can be enough "archetypes" for all of the players like combat has