Recent update makes me finally post this idea since now there is a lore reason behind giving enriched health hypos a small regenerative effect. I'm won't say what exacty it is to avoid spoilers, it's related to this change:
New entries in the Institute of Tchort library, some of which contain blueprints and will require a special card
On Hard and above hypos are virtually limited to 1 per fight for vast majority of battles due to extended cooldown. 1
5% 10% chance to benefit from enriched health hypos per battle is... not really exciting. I don't imagine them being much better on Normal.
Moreover the crit can happen when there's no need for it. Noone is going to be using enriched hypos as if they were going to crit because of low chance.
Most of the time they are no different than regular health hypos.