Then you get a pumpkin who want to play we had 2 or 3 of them. They take a cleric who refuse to heal, a strength based PC with 12 strength or some other moronic concept.
What's wrong with a cleric that doesn't heal? The cleric domains are pretty good at not needing to be healers. Not they best, but I wouldn't shame a player for doing so. The 12 STR fighter isn't all that far behind either. If you talk to them, see if they'll be reasonable enough to bump it to 13, so they can use chain effectively. Or, they can wear the chain anyway. The penalty's only 10 feet of movement, or they might be a dwarf, so it's fairly reasonable to wear chain with low STR if you plan on being the one who's blocking tight corridors, rather than the one doing the damage.
Or we need a healer so the plan is to take a thief with the healer feat but then they take a arcane trickster take a non human and at level 4 buff intelligence and charisma. And then the party gets takedown.
I think this one needs a bit more story. Did you at least
talk to the player in question before building around them doing this, or did you merely assume they'd be the healer? Did you talk to them afterwards to see
why they decided they didn't want to be the healer?
D&D is a team based game. If the party needs a healer the last PC rolled up should be a healer or whatever the party needs. When I play I normally take the last role that needs filled.
I don't agree entirely. D&D
is a team based game, but a player shouldn't feel like they
need to be a certain concept they don't want to play, simply because of peer pressure. Instead everyone should look at what they want to do, then see what holes aren't filled, then adjust as necessary. Sometimes a hole isn't nearly as big as initially suspected.
I know my own group has been able to accomplish the "healer" role with just
potions of healing. Was it efficient? Not really, but that's more because initiative screwed everyone over, which wouldn't have been solved by a dedicated healer.