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If you move the regeneration ability to level 4, wisdom won't work, and you'll have to remove something at level 4 (which is already a loss of two possible upgrades), and regeneration is sometimes used even at level 5 for creatures, etc.
Changing regeneration in the way it is currently implemented in the mod is the most "minimal-optimal" approach.
Well, plus or minus two useful changes won't make much difference if it's for the greater good, but it's up to you.