Let's imagine the situation in X-Men : Deadly Genesis was resolved differently. Xavier got thrashed by Cyclops and Co because he was lying to them fom years and then exiled; and somebody convinces Vulcan to join X-Men (after all, after M-Day the mutants need all the big guns they could get). Darwin stays with Vulcan to make sure his friend doesn't fly off the handle again.
 
How do you think Vulcan joining X-Men can change the story of Earth-616?

I dont know what would be different..after all there is no many options but what i know is, it would have been awesome to see both vulcan and darwin as x-men! I can see vulcan being a pain in the a** for cyclops as well as being there biggest gun!

Let's imagine Deadly Genesis wasn't a giant pile of awful, and that Vulcan simply encountered the X-Men and didn't have his head up his ***. I actually like that idea.

Id be interested!  Anything to shake up Cyclops!

in the what if vulcan defeated magneto thus becoming the leader of the x-men.... but it was also because the originals plus Havok & Polaris died( except cyclops).