Undrave
Legend
In 4e, you do add your full CON score to your HP so if you increase it, you do gain a few extra HP. Not as much has changing your CON mod in 5e of course.In 4e your Con didn't increase hp by con mod per level. In 5e it does. This has a significant effect on tankiness in 5e. It's a huge difference. And one that I honestly cannot believe you are downplaying. Making a con caster in 5e would be terrible from a game balance perspective. I mean I get it conceptually and it does have a conceptual place - but unless con only marginally increases hp it's not something able to be placed into a game.
*In 4e con most notably increased your number of healing surges - primarily increasing how many encounters you could go through before a long rest on an adventuring day.
If you're too affraid of too much HP just give them d6 HD. It'll balance out to be worth a d8 HD for someone who took CON as secondary. Give them only light armour proficiency and no incentive to get good DEX. We're talking about a +3 CON at first level versus a +2 on most character who are scared of being hit. If you don't consider +1 or +2 CHA to be significantly weaker at social skills than +3, then the difference between +3 and +2 CON shouldn't feel that great either.
It's a tengeant for sure as we discuss the value of ability scores. But a CON caster would open up Sorcadin style shenanigans for the Barbarian and Fighter. It's at least something INTERESTING you could do with your physical score, even if you don't remain purely martial.I think a CON caster would be cool and could probably be balanced with hit-dice and armor options (though multiclassing makes that hard) but isn't the crux of this argument about casters vs martials?
How about spending Hit Dice instead of HP? That's ALSO a daily resource after all. Could work a bit like Sorcery Points but a little stronger.Spending hp for effects is also a nearly impossible to balance mechanic with characters that cannot do so. You always end up in a situation where spending your hp for a spell saves more hp or where it saves less. It also lets you indirectly convert your hp into allies hp (defacto spreading damage). Given that you start with more hp this way and given how concentration works, it essentially makes already versatile casters much more versatile and stronger.
And I guess the biggest issue of all, healing restores your spells and it's easy to get out of combat healing to be super efficient. How on earth does something like this get balanced in 5e?