Definetly look into strapless if you want to not go as "full on". A thruster also helps here. Strapless really limits you and helps you stick within the confines of prone surfing while kiting. And it is way easier on your body.
You can take it easy with a quad and straps, but you actually won't have the limits. Very quickly you will be doing things you could never do while prone surfing. And you will realize that having a wider performance envelope with straps and a quad, will demand more from your body.
To each thier own......or rather - sort through the hype for yourself.