I thought that it was creative to have a Corps that was always boiled down to one representative, as opposed to all others which were always about recruitment. Avarice was also a good explanation for the Vega system being off-limits, as well as why the evil forces of the universe were attracted to Vega.
Larfleeze himself is billions of years old, and can hardly be expected to “grow” once he left the confines of Okaara.
Of any conflict, the Orange Lantern Corps was most interesting when Lex Luthor became another Orange Lantern (at least without being killed first) and got into conflict with Larfleeze.