My comment re carrier speed is from a statement a long time ago to the effect that with the STOVL and ski jump the electric engines would only need to make approx 20-25kts (into wind). If you are now considering a cat launch for F18 or similar (unless the g loading really is phenomenal) you need a carrier with considerably more grunt - iirc Ark, Eagle, Victorious et al were about 10kts faster, and what is the normal launch speed for US carriers at the moment? I won't even raise the redesign of the flight deck assuming angled operations are considered essential.