Estellios, you are incorrect.

Recovery now will work like this: the longer you take no action the faster you'll regain HP/MP
so that means you get increasingly more HP/MP with each tick that passes. so first tick +10 2nd +20 3rd +30 ect ect.

So now since we can cast while in passive mode that means we can gain enmity while in passive mode. Other wise you could cast and continue to recover at a increased rate.

SO if you cast a spell and incur enmity it will reset your recovery rate back to 0 and you have to start over.

We will still be able to recover even when in middle of a battle.