Remnant of Asc... mana regen scaling

it's passive Favor replenishes 6% of missing mana when grabbing blue coins.
this makes the item scale better with flat mana items.

however If I want to build anything that uses I do not benefit as much as from

could it perhaps scale by like 6%+(0.5% per 25% bonus mana regen from items)

might not sound like much but sometimes having enough to cast a spell at a critical time can make all the difference.

or how about: it could only be based on base mana not max. or work like Sheen does but off a universal base mana. so I guess like gives back 10+1 per level or something.