realize that none of these changes will affect damage output or heal output. They are, for the most part, all changes to increase mobility and utiltiy of the Merc class.
For starters the changes you said to Combat Medic would actually increase healing done.
"allow Kolto Shell to be applied to an unlimited number of allies, and reduce its heat cost to 8"
This would be 2400 heal to everyone and not just 4 people
"reduce cooldown of Emergency Scan to 18s"
Faster 6300 heal
None of these changes you said would be viable. It would break pve too.