The Healing Factor still costs the same. You're able to purchase up your regen (and it's, honestly, really cheap considering what it does), but the ability to heal is incredibly valuable. I also feel that the maintained price of Healing Factor may have been a reaction to SO MANY characters being built with a Healing Factor simply because, in order to be effective, they need that regeneration. Now, the characters with Healing Factor are the ones that, thematically and not mechanically, need to Healing Factor.
He summed up my feelings on the issue and reasons for the choices I made (and that's just speaking for me, there are plenty of different versions of this rule floating around, your mileage may vary).
I may be misunderstanding something here, but numerous times I've seen things in the books suggesting that you can alter, or even create, your own actions/modifiers/challenges/advantages/disadvantages.
I would argue that it should be possible, with GM interaction/discretion, to allow a player to take leadership as a modifier, at M# +2 (or 3) with the built in disadvantage of Doesn't Help Others, but doesn't reduce cost (this is just off the top of my head, right now), but you can buy advantages as normal, as long as it would make sense in this format.
Here's how I would right it out...
Deep Reserves (I like that name) M# +2 The character gets 3 stones from the general pool, each panel, to split between their 2 actions per panel. You must split the stones between the actions (no dumping them all in one).
In essence, you could get the bonus stones, just like Deep Reserves in the original post, but at a reasonable cost for just a few extra stones.