Nicko's situation (although studio is not like a tour) may be one of the reasons why (for now) we think they have no desire to record another album. But I remain optimistic, especially after his latest interview, in which they hide his answers on this matter.
Will Maiden change their live way of recording albums now? Dunno, but who knows, they changed the drummer after so long.
Nicko playing just a couple of easier songs (like Writing)? Possible, but it would be odd and it depends on whether he wants to. I think he will. He should be able to maintain fast tempo and steady/solid groove (powerful enough hits, good drum parts?), right? Or? Maiden can/to use ''studio magic'' for his takes? Not that sure. But I think Maiden can benefit (to say) from some studio magic now. Why not. The recordings will be longer, will they want this?
Recording an album more-mid tempo than the latest one wouldn't be good. Now, they should record with Nicko soon, when he is still in touring shape, and the age factor. It's realistic, right? The band want to play with him in the studio.
Simon is a live member, so idk about recording, but he would be the choice (after they see the tour with him). I really don't know why Maiden don't want to hurry up with the new material like all other bands.
Nicko to still write/arrange drum parts and give ideas... who knows, but he will want to play them I feel.
Kevin will be used for the production, no doubt.