The ending wasn't remotely the same, in the comic the alternate future was avoided altogether and Sen. Kelly's life was saved. In the movie Magneto proved oncreen that mutants can be and are indeed dangerous. Not mention the illogic of having Kate Pryde somehow take Wolverine's mind into the past. Kitty's ability is be able to phase people and herself though solid objects not navigate minds though time and space. Wolverine's actions in the movie didn't change Mystque's mind to make her give up nor did he stop Magneto.
the dark world was not avoided in the future. I remember there was follow up book called days of future present.
I think people are giving bryan dinger to muck of a hard time for given kitty
secondary mutation.
Think of it this way.
an alternate emma starts off as a telepath then as time goes by she develops secondary mutation by changing her skin to diamond.
in the original comics, kitty goes back in time but as that would have been illogical in the film universe it was only fair kitty be the one to send another person back in time.