In my experience the roll aboard a proper aircraft carrier was never too much of an issue.. Twas the pitching that would spoil a pilots day, and that even applies to the huge Nimitz class carriers.
I am saying this simply to try and present a balanced presence on this emotional topic and yes carriers are effected by the forces of mother nature and for the conventional aircraft carrier this will always have to be a consideration.
For the vertical landing of an aircraft then I would suggest anywhere aft of perhaps just frrd of amidships would be possible in most seas as contrary to most land lubbers opinions the most stable place on very large ships is possibly the aft area of these vessels (I include Illustrious in this category)
Which means the Harrier should be able to remain operational in seas that would stop flying on conventional carriers. (I am still a fan of the latter)
On any ship the worse place is obviously at the pointy end and in rough weather standing in the cable locker of an aircraft carrier equates to being in a lift that is continually going up and down up........ and down, up.......... and down
