The ultimate solution to this is for shops to have a demo kite or two
in stock. Many of the claims of performance and control in the past
have been quite exagerated and a simple test fly can easily check the
claims and assess the suitability of a kite.
It's true you can't really give a kite to a beginner to test fly but
there's plenty of strong intermediate to advanced kiters out there
ready to spend money if we know the gear is better than what we've
got. I've taken a punt on gear in the past and it was expensive and a
little disappointing and I've bought gear after a test fly of
friend's gear and been very happy with the result.