I think its time Riot realizes their Karma rework has been a failure. Seeing as no matter what they do to her she is either completely useless or extremely oppressive. I believe this is due to what they turned her kit into, it was turned into a "jack of all trades" rather than a given a singular direction. She was given to many tools, while at the same time taking away part of her identity.
Here is my suggestion for an actual direction to take her, rather than leaving her as "can do anything" champion. The direction you ask? well a Spell Casting Mage or Enchanter direction, but mostly as a Burst Mage. You will notice that a lot of her Base Damage is lowered, while her Ratios are increased, this is how you keep a champion from building tank and still doing damage, you give them incentives to building AP.
For some of the Old Karma players out their you will see that I did a lot of combining her Old Kit with her New, I think this way it gives her more of a direction to play as (Mage) rather than being able to fit to many spots and being constantly to strong or to weak.
Innate: Gathering Fire, Switch back to Original Innate with more modern scaling.
Remove: CD per hit on enemy champion
Add: Karma gains .5/.75/1% AP Per 1% Missing HP. 1/6/11
Q: Inner Flame, Stays the same with # Tweaks
55/95/135/175/215 (+.75% AP)
35% Slow, 1 Second
Mantra Empowered Q: Stays the same with # Tweaks
Additional damage on initial explosion:
20/30/45/60/75 (+.25% AP)
50% Slow, 1.5 Seconds
Secondary Explosion Damage:
1 Second Delay
55/95/135/175/215 (+100% AP)
W: Spirit Bond, Changed name back to Original as well as major changes
Initial Cast: Links Karma's Soul to an Enemy or Ally for 2 seconds.
Ally: Healed for 45/75/105/135/165 (+.35% AP) Over the Duration.
Enemy: Damaged for 55/95/135/175/215 (+.50% AP) Over the Duration.
If the Bond reaches its full duration the Bond bursts giving the Ally Movement speed, or slowing the Enemy.
Ally: 40/45/50/55/60% Movement Speed for 2 Seconds.
Enemy: 25/30/35/40/45% Slow for 2 Seconds.
Mantra Empowered W: Changed name back to Original as well as Major Changes
Karma now heals for 45/75/105/135/165 (+.35% AP) Over the Duration.
Karma heals for 5% of her missing HP per Ally or Enemy affected by this ability.
Allies who pass through the Link are healed for 6/7/8/9/10% (+1% per 100 AP) of their Missing HP.
Enemies who pass through the Link are damaged for 6/7/8/9/10% (+1% per 100 AP) of their Current HP.
The Ally or Enemy Linked is affected by this on initial cast, as well as at the end of the duration.
E: Soul Shield, Changed name back to Original as well as some changes.
Shield a target ally for 20/60/100/140/180 (+60% AP) for 2.5s
Movement speed Buff: 30% for as long as the shield is up.
Mantra Empowered E: Changed name back to Original as well as some changes.
Now Explodes on the Target Ally.
Explosion Range: 500
Allies affected gain 25% of the Shield value, and a 30% MS Buff for the duration of the shield.
Enemies affected have their Magic and Armor Resistances reduced by 10% for 5s, as well as taking 50% of the Shield value in damage.
R: Mantra, Minor lvl 4 Ability Change.
At lvl 4 of this ability Karma gains 1 Charge of Mantra every 20s, and can hold up to 2 Charges.