Right now, when your CON is modified by anything, only your maximum health is modified with it. If the difference between your usual CON and buffed CON is large enough, you end up going from 100%/100% HP to 10%/100% HP. (Prime Example: Transposing from Full Int to Full Con)
This kinda wastes the functionality of such a buff, which is meant to obviously make you able to take more hits, but you only end up with more maximum HP and are just as squishy as you were before the buff until a cleric heals you or you use a ton of potions.
Now what I believe should happen, is that you should always keep the same percentage of HP remaining. For example, if I have 1500 HP, and I have 750 HP remaining (50%), and then use or receive a buff that influences my CON increasing my HP to 2000, I would end up with 1000 HP remaining for the duration of the buff. Once the buff runs out, I would again end up with 750/1500 HP, assuming I didnt restore any of it.
Having 50% HP left would always be 50% HP, even during or after a buff that influences your CON, so your HP bar wouldn’t visually change besides of course showing larger numbers, and actually making you capable of tanking more hits.
Thoughts?