New Karma doesn't play at all like old Karma.
Also, new Karma's damage output was greatly reduced, but her utility was increased and is more reliable (speed boost moved to the shield - slow added to her Q)
Her Q was also made to be a better poke, so Karma isn't such a short-range mage anymore.
My final decision is that she'll make for a good support, but her solo-lane ability will be WEAKER than current because her E requires the long CD mantra to deal damage, so she has to level W for damage trading, which means less durability in the trades since the shield will be weaker.
To be honest, new Karma will make supports happy, but AP Mage players sad.