I've been sailing a Nacra 5.0 for quite a while before changing to a Blade last year.
The F16 is a lot faster, but as easy or even easier to control. I don't think you get a lot wetter on the Blade then an other cat.
My dad is 60 and has been sailing for 10 years on the 5.0 (mostly with me as skipper) and he didn't have any difficulties changing to the Blade also.

Just be careful hitting something (with every kind of cat).

Regards,
Gill