I`ve heard the title "Secondary Mutation" thrown around quite a bit recently, and i`m not to sure it`s applied to what it really means. What happened to Beast and Iceman to me is not secondary mutation(whethere it`s cool or not), it`s more like Evolution. You`re a cat man who becomes even more a catman. Like Cyclops had more power after Giant X-Men 1 so needed a new visor, right?
To me, secondary mutation is something new, something not related to what you had before in any ways. Sort-of like remember when Polaris lost her magnetic powers and got bigger and began to have super-human strength? THAT`S secondary mutation to me.
Also, what would you guys want to see more happen to you favorite mutants, some sort of evolution to what they were, or an entire new sets of powers? Or even same powers applied differently(like a telepath using her powers as a psy knife). I think in any of these cases it could be fun.