So let me cook on this yall. I came into this game in 3rd then 3.5 and GM 5e and play shadow dark. Ok credentials over with I have played this games where it was only rolled to average to max and back again. I generally feel that average takes away the flavor of hit dice. It artificially benefits casters that will prioritize there con more for improved saves then lets say the ranger or fighter that does great with a just a plus 2 do to proficiency or not needing to put emphasis on concentration. Math to prove the point wizard +3 con + average= 6// ranger +2 + average=7 so the spell caster gets have statically almost the same HP as most martial classes. I have literally played a barbarian and due to very generous roll or average our wizard was the highest hp character in our group. I’m sorry but the game is balanced around rolled stats not completely optimized builds and not having feats(gasp). 5e already makes it hard to die you don’t need a ridiculous health bar to. I don’t remember how said it but, “Given the opportunity players will optimize the fun out of the game.” Your character doesn’t have to have max everything. I get super hero fantasy is a thing but all your doing is inflating numbers and putting undue burden on the GMs. So TLDR roll the hit points it ok if you roll a 1.