The Kumari is a great ship, imo. Well, depends on your class. I suppose if you're a Tac, you'd be better served on a Defiant, Patrol Escort or HEC but for a Sci and Engineer, the Kumari is probably one of the most powerful Escorts available due to it's BOFF layout and 5 fore weapons slots.
The Wing Cannons are decent but really pack a punch with the Phaser Dispersal Array console. You get 10% bonus accuracy with 2 consoles. I admit the Wing Platforms are pretty weak and not worth the console space.
As an Engineer, it's my preferred ship until Cryptic fixes cruisers and/or adds a Fleet version of the higher tier ones.