Oh true. yeah I completely forgot about his lyrics. he's lyrics are far more creative than most rappers. But Flow wise I think dudes like Rakim or Krs-one have him beat by far. Also, there are hella rappers who don't talk about how dope they are like Q-tip, or posdnous. Personally I like de la soul, tribe or the pharcyde because I relate to them more than most rappers. Do y'all relate to the shit Doom says? cuz I just don't. if I did I'd prolly think he's a doper rapper.
If skill = relatability then you're going to have a hard time enjoying 99% of art. But that's besides the point. MF DOOM is not someone you relate to. He's an exaggerated persona, a character. A supervillain, modeled after Dr. Doom, There are bits of Daniel Dumile in MF DOOM (DOOM may have been born from Dumile's tough career in the music business), but they aren't the same person. In fact, Dumile works under a few different aliases (King Geedorah and Viktor Vaughn to name a couple) with their own special quirks/aspects (although one can argue that Viktor Vaughn and MF DOOM are the same person, only that VV is a sort of 'prequel' to DOOM).
But as far as skill, I'd say that DOOM is damn near in a league of his own. His technical rhyme abilities are solid, but his most notable talent is his wit:
Some come in the form of codependence
A lot of times only end up being codefendants
Ten bucks say they tell for a lower sentence
And leave you up under the jail, begging for a penance
It don't make no sense, what happened to the loyalty?
Honor amongst crooks, trust amongst royalty
I'd rather go out in a blaze, than give 'em the glory
(How many of us have--) a similar story?
(Deep Fried Frendz)
Here we see DOOM's paranoia at it's peak; the codepedence/codefendants wordplay portrays DOOM's distrust for others, his belief that "friends" can only end up controlling you or betraying you, and his will to destroy himself in order to deny others the pleasure. It's really fantastic wordplay not only for rap, but poetry in general. You can really see the influence that Bukowski had on him here. As The Jackal said, a lot of DOOM's lyrics are often dense, and they require more reflection than usual to really "get". There are a lot of really straightforward DOOM lyrics out there, but they always come with a sort of sardonic flair to them, to the point where most of his songs/lyrics are nihilistic in their bleak portrayal of life in new york and society at large and the state of rap today.
Sorry for the wall of text. I'm a huge DOOM fan. His music has influenced me immensely. Great musician. I hope you eventually come to enjoy his music as much as I do.
Also you might want to do some fact-checking on your post there, Q-Tip and Posdnuos has definitely talked about how dope they are in their songs. Not that that's a bad thing, quite the opposite, actually. Rap was founded on talking about how dope you are. Rapper's Delight is basically 20 minutes of dudes talking about how dope they are.