Pizzati is a Porsche and Audi driving instructor. I can tell you he wouldn't have got that gig unless he was a very good driver and equally good communicator. I can tell you those guys don't putter around doing "normal" defensive driving. Porsche focus on racecraft training.
Cox was an ex racing driver too but a crap presenter. You can read more about the original crewhere.
Now I like James May, however I disagree with you on his similarity to James Morrison. May is a trained musician but is a career journalist.. James Morrison on the other hand is a career musician (with exceptional talent) and his hobby is cars. He has competed in a number of Targa style events. I think Morrison is an excellent choice and is showing potential already IMHO.

