Mags is smart...a genius...but still, do u understand how my top 15 guys operate? Do u know who they are? Reed Richards and Doom go without saying...believe me, they know much more about genetics than Magneto. Magneto may have created some genetic freaks in his day, but Doom and Richards really dont have anything to gain by making genetic grotesques. Reed and Doom deal with much more complicated stuff on a regular basis...
By the way, Maximus has done ten fold of what Magneto and Sinister have done with genetics. His people (the Inhumans) have been doing genetic engineering for tens of thousands of years. Alas, lots of people dont know who Maximus is.
The Leader: do I really have to explain why the leader is smarter than Magneto and Xavier?...just look at his head, not only does he have greater knowledge than those two, but he has superhuman intellect and calculating abilities, he has a super evolved brain, Its like comparing our brains to a chimp's brain.
Agamemnon: A Diety like being, thousands of years old, leader of the Pantheon, he has god-like consciousness...again, easily more intelligent than Mags and Xavier
Nathaniel Richards: Father of Reed Richards, Immortus, and has hinted that Doom is also one of his descendants. A complete master of time travel, moreso than Apocalypse, he barely even appears in our time anymore, but he has demonstrated greater skill in time/interdimensional travel than Doom or Richards...while Doom was prisoner of Hyperstorm, Nathaniel was crashing at Castle Doom for some odd reason.
Immortus: Im not even going to go through this explanation...but he is easily smarter than Mags and Xavier...before the time keepers practically made him omnicient, he had already lived through some 80 Millennia. http://marveldirectory.com/individuals/i/immortus.htm
The Sphinx: Originally one of the priests of Pharaoh, defeated by Moses...eventually granted Immortallity...eventually absorbed the sum knowledge of Xandar's planet sized computer! (this guy is smarter than magneto)...oh, and he went one on one with GALACTUS!
Apocalypse: Five thousand years old and still tinkering with Celestial tech...by no means as smart as the previous guys but definitely on the high end of the intellectual food chain on Earth.
Kristoff: Possesses the sum knowledge of Doctor Doom from back in Fantastic Four issue two hundred or something...although he is only a kid, he has demonstrated he is vastly more intelligent than anyone below Richards like intelligence. He has also proved he could quickly interpret a plan of the Watcher (the watcher is smarter than magneto and so is this guy) and decipher, manipulate, and assemble, Watcher technology without prep time...he is actually probably smarter than Apocalypse.
Modok: An artificially mutated human turned into a super computer...possesses super human intellect (beyond genious)...created by AIM, later was the leader of AIM....MODOK: mental organization designed only for killing)
Quasimodo: Artificial being created by the Mad Thinker, has a link with Xandar's planet sized computer...
Mad Thinker: Basically dominates over almost anyone but the leader and the Richards in terms of calculating and "intelligence"...I wont explain him unless someone asks me to...but he is smarter than Magneto and Xavier
Is anyone getting my point?....I know these guys weren't on the X-Men cartoon, so some people probably didnt know how they were in an entirely different category of intelligence than Magneto and Xavier