No I didn't ask if it's been that way, I asked if it would be op if they were allowed to stack. Then I asked for examples of how it could be over powered, while providing numbers to the best of my ability to show it is strong but I didn't think overpowered at low levels, but at higher levels it balanced out and was a utility tool but not exponentially overpowered.
The answer, thats the way we always do it is the worst answer because it has no value other than "someone told me so". no analysis of interactions or mechanics, just "it's that way because it's that way".
I quoted other ways it's OP. I'll put them down in numerical oder.
1. With 15 hp at lvl 1 your twice as healthy as anyone else.
2. With rage that 15 hp effectively turns into 30, so now you have a level 1 barbarian with close to 50 hp. Rage halves all weapon damage, and at level 1 thats usually all your taking. Later it can do the same for pretty much all effects save psionics. I believe it's psionics/force maybe wrong but theres only 1 type of damage you wouldn't have with a barbarian.
3. Same goes for anything that has blade ward cast on it. effectively doubling your hp by taking only half damage.
4. Vampiric weapons or any weapon that gives you health on hit, fiend warlocks Dark ones blessing works as well. So you if you heal temp hp won't ever run out of those extra hp. Though don't think you can. So might be a mute point. Still we are in what if mode.
5. Taking potions of resistance has stacked with some other resistances, such as barbarians rage. So now the barb is taking 1/2 then halved again damage. If allowed to happen. So again his starting 30 hp is now up to 45 hp from temp alone. thats at level one. Later it gets worse with the increases to what is supplying you with temp HP.
6. So you can see where with anyone that multiclasses in barbarian turns into the Hulk/wolverine pretty much. Which causes every other class to simply be there. and people will multiclass into barbarian just to do that. Theres already people going ham on barrels, shoves, etc, and freely admit to it.
7. With simply a Barbarian their would be little worry about having to expand an action or bonus action. he's already doubled his temp hp by simply raging.
8. there are ways to do simillair to barbarian with the other classes as well. Not as bad but still in the end broken.
