It's not the same. Small Life Potion heals part of your max hp on a time basis. Regeneration Potion increases all future and incoming heals (be it item or spell) by a very large %. Imagine a reverse critical wound that lasts 30 min.
It was deemed bit too strong in its original state a year ago, but its effect was taken and put on the Drops Cake Hat for a custom hat effect that only lasts few seconds and not 30 min upon being hit~
Life Tree Shoes would have a similar effect as Regeneration Potion already (if it's not broken...)
