He has a penchant for self-deprecation. There is nothing impenetrable about his F4 run, or his Avengers work. They are much more thoughtful than most mainstream comics. However they are as deep as you care to go if you want to go down the rabbit hole, plenty of ancient mysticism and meta commentary about comics, but overall they are fun and just good solid modern comics.
I would have been crestfallen if Marvel had lost him. On the other hand I might have followed him across despite not fully understanding the properties he would have been working on at DC.