Kweli been dealing with people downplaying him for years so it's nothing new. Is he Mos or Common...or Black Thought? Hell no. But for a time he was on a very good run, and while his flow can be off putting at time you can't call him a bad rapper.
To me he's just not "that guy" the other the other rappers I mentioned are. Respiration is the perfect barometer to me. You get a classic verse (and hook) from Mos. Classic Common verse. And Kweli is kinda just there - admittedly with a solid verse. And that Kweli playbook is def the lane most "backpack" or underground rap went in. Less introspection, less emotion, less feel IMO. Think about how introspective Common is on that song, or how evocative Mos is.