1. Since Shake it off was took an exemple, just revert back to the way it was at the start : without the group heal.
The majority of its strength is still the initial mit.
2. Remove the level 94 boost of Second wind
Given Maim and Mend, this amounts to less than a Cure per fight.
Then you run the risk of making it not an available tool at all against many sequences of attacks, which effectively removes its engagement. These matters quantize.
See #2.
I'm guessing you mean charges, as none have stacks. See #3.