Karma = Lux with 2 support spells instead of 1, and 2 damage spells instead of 3.

Of course if you expect her to leave every last hit to someone else she's useless. She's a stat-based champion (as opposed to a hard cc support that doesn't need items like Janna) so she needs farm, but in return you get very decent damage along with frequent shields on the carry, and she can trade in some of her damage for heals when the Twitch hits the fan.

Think evil tome and go from there.

I think rod of ages and then i think of another rod of ages and i contemplate CDR boots as well at some point
But that's just me probably, and tbh if i wanna play offensive support i will play Morgana.

Boots are not enough, Karma synergises so well with CDR that you'll need dedicated CDR items and evil tome also has AP and enough mana regen to solve all your mana worries. CDR even equals survivability: shieldhealshieldheal trolling can keep an enemy busy for a decent amount of time while your team beats on him.

Of course Morgana is better. There are about 10 "best" champions in the game, so not being the best is hardly a problem. However claiming she's a horrible support compared to Janna is like saying Maokai is a horrible AP burster because his ratios are too low: it is true, but it is also beside the point.

2.7 AP vs 3.76 AP. It's also beside the point I'm trying to make.