The Geezer album Black Science had a lot of keyboards and it did not work.
For me the most difficult thing is that I am learning melodies on guitar from some songs whose melodies were not meant to be played on guitar. Ever. They were intended mostly for keyboards or melodic percussion.
I've always been into guitars... we want to put keyboards on but keyboard players don't look cool onstage they just keep their heads down. There has never been a cool keyboard player apart from Elton John.