Am sorry for the rant.
Level 17 4* troop = 11% mana regen.
Average hero = 10 tiles to fill.
9 tiles * 1.11 = 9.99 presumably, doesn’t fill with 9 tiles after testing. Shame on me I suppose for thinking differently and giving the benefit of the doubt but this is astonishingly poor for the level of investment to get to that level. Yay, can take a slow hero to 11 tiles, which matters not at all for 99% of the game given how awkward slow heroes are in general.
It’s still a marginal if not outright wasted modifier compared to the other 4* troop which has zero useless or even not quite useful modifiers. Heal bonus jury still out on with the 1.7 patch where it was increased, but the mana regen 4* still seems like a waste to invest anything in even compared to a 3* crit strike troop.