Yeah, I'll be applying some kind of penalty for wearing armor. Haven't decided exactly how to handle it yet, but I'm doing something similar right now with my PCs while they're on Athas. Chult's like the opposite extreme.
As far as such a ruling penalizing some classes or characters and not others....that's not really a concern for me. I try to make sure there are challenges for each character at times, and ultimately, I want to challenge the party. So their heavy armor guys having to take a drop in AC fits, so it works for me.
EDITED TO ADD: I think I just decided how to handle it. Here:
- Not consumming 2 gallons of water in a day= a level of exhaustion with no save
- Activity in light armor- no save needed needed
- Activity in medium armor- CON save or level of exhaustion
- Activity in heavy armor- CON save with disadvantage or level of exhaustion
I'll have to figure out the DC though....don't want it to be too steep. Maybe have it scale? DC 8 + 1 for each consecutive day of activity.
What do you guys think of that? Similar to some other ideas in this thread, but a little different.