My proposed "quick fix" for Karma. Changes are highlighted.
Passive - Gathering Fire
Karma reduces Mantra's cooldown by 2/2.5/3 seconds every time she damages an enemy champion with an ability, halved to 1 / 1.25 / 1.5 seconds when using basic attacks **or when affecting other allied champions with spells. This ability can not reduce the cooldown by more than 4/5/6s per spell. **
Q - Inner Flame
Unchanged
RQ - Souflare
Inner Flame travels (harmlessly) through enemies to target location to deal bonus magic damage and leave an area of effect that lasts 1.5 seconds, slowing enemies inside by 50%. The area detonates at the end of its duration, dealing magic damage to all enemies inside. If Soulflare does not hit a target, the area is created at maximum range.
W - Focused Resolve
Karma forms a tether between her and the target enemy champion or monster, dealing magic damage and granting true sight of them for the duration.
If the target does not break the tether by moving out of range, it deals magic damage and they are rooted for a short time.
If targetting an allied champion, instead of dealing damage Karma increases her and their resistances by 5/10/15/20/25/30 (+1 per 100AP) as long as the tether persists.
W - Renewal
Focused Resolve deals bonus magic damage and heals Karma for 40/80/120/160 (+1 per 20AP) increased by 3% for every 1% health she is missing, once upon being cast and once more upon rooting its target, with the root duration increased.
**If targetting an ally, Karma gives up this heal to grant it to her ally instead. **
E - Inspire
Unchanged
RE - Defiance
Inspire overflows with energy, increasing the target's shield, dealing magic damage to surrounding enemies and shielding all allied champions near them for a fixed amount and a percentage of the damage dealt, while granting them a fixed bonus movement speed.
R - Mantra
Unchanged
There. Doesn't need a full VGU to make a battle enchanter. A real designer could probably do better, but it's the best I could come up with so far.
Explanations
P - Should interact with ALL of Karmas abilities, not just the offensive ones. I tried capping the passive to keep her in line.
Q - Unchanged
RQ - Making it a targeted ground ability ensures Karma is not encouraged to fight at max range anymore, but thrives in close combat instead, even if minions are hugging her.
W - Ally function to offer "enchant-y" support qualities at expense of damage/CC. Note how this allows you to stay in battle next to your friends.
RW - Health scaling that fits a mage and ally function that fits an enchanter. Removed annoying root because nobody likes it.
E - Unchanged
RE - Shieldbomb again, rewarding hitting many players of both team and discouraging simply targetting your team all the time. This adds a well needed skillcheck to this ability and makes it useful for mage Karma.
R - Unchanged
######PS: Yes, those changes would also mean a lot of number changes to her values. I tried keeping it short and simple tho.