I don't think most people understand the reasons for the redesign.
In gen II/III, all of the gym leaders were kind of dicks, and like most of Kanto, had a rather depressing or power-lustful attitudes.
However, in gen II/IV, after Red has defeated them, they lighten up and realise it's not all about power, which is why they are much friendlier, to Ethan, and dressed more casually as a result.
