General Changes:
Get rid of dual wielding and replace it with a single gun.
Change Stash so that it is a resource of 3>4>5 (add Secret Stash II as a trait) that has offensive uses from MSK and gets additional healing/support uses from CHM.
MSK Changes:
Fix the combos: Hot Shot shouldn't be a tier 2 combo attack that's part of the flat damage combo if it has a long DoT duration; provide a full flat damage combo as part of MSK instead of requiring COR; provide 2 separate full ST combos instead of one 4 part, one 2 part that can turn into a 3 part but is only for AoE.
Remove stashed Remedy and stashed Hi-potion.
Add offensive/utility Stash consuming abilities (Explosive Round) and change existing abilities (Sleep Shot, Quick Draw, Drink) so that they consume Stash stacks (not all of those would necessarily be changed, just listing some that could be changed)
Reevaluated Ironhide Ungent (esp. Ironwill Ungent) and Sniper Shot
CHM Changes:
Get rid of gear changes as part of Throw Items.
Decide whether maintenance healing is intended be done through cross-class Cure/Physick or unlimited cast MSK Potion.
Add Windfall Ether (or some other resource returning ability that procs off of crits) in place of Mega-Potion.
Turn Hi-potion into a flat cast.
Turn X-potion into an off-GCD large heal that consumes Stash.
Change Pharmacology to Stash refill or cost reduction ability.
COR Changes:
Get rid of Loaded Deck and simply transfer the card gaining abilities as additional effects on all abilities. Conversely, have Loaded Deck turned into a limited uptime stance that spreads card buffs to all nearby allies.
Reduce buff value of cards. Get rid of +acc and replace with something more useful, like +attack speed.
Reevaluate all +skill speed buffs and/or change to +attack speed buffs.
Modify support capabilities so that they are not global and are instead specific to certain roles/class subsets.
Reevaluate card generation/maintenance/consumption mechanics and limit number of total cards at a single time (without limiting card type)