As a Karma main, let me tell you the following:
I have played her in every possible lane and i will continue to do so. Your whiny opinion will not stop me - nor will it stop any pro for that matter - to continue successfully playing her support.
That being said:
No hard disengage, no hard CC, no hard stat enhancement, no clutch saves, low turnaround potential or playmaking ability. I guess it must be boring.
Other supports offer more safety. Or damage. Or carry potential. She's got some of all. But I can see why you would prefer a specialist or a support with harder impact. Karma feels mushy to play with, and since her carry potential is usually in pure damage (her fun) or huge damage absorption (feels low impact), you don't get as many opportunities to shine, as you would with others.
Again, I do understand that you might prefer otherwise. But your attitude sucks.