That sums it up I guess...
I would add that the ability to pick good beats (and reject the weak ones producers give you) should be included in the criteria used to assess MCs
i think for Dubee it aint even really that player. producers like Khayree, for instance, want to
produce records, not just do the music. i guarentee you "Dubee aka Sugawolf" (his best, and one of the best albums ever in general) wasnt just Khayree on the beat and Dubee on the lyrics. these producers have a vision. thats why Snoop/Daz/Kurupt and them's best shit was produced by Dr. Dre. Khayree's the Stargate/Rock Mafia of bay rap music. but like everyone i mentioned, you have to have a good artist to work with, or atleast one you believe in.
dude in my sig is one of them producers. part of electro/soul/hip hop group TV On The Radio, and Janes Addiction, and solo writer/producer for Maximim Balloon. those kind of cats produce more than a beat.
as far as Coolio on the beat, i think thats more just beat and lyric type shit but i like Dubee on Coolio. but any artists will atleast get a listen from me if its over Coolio.