I've read this several times, and I'm not sure if you are supporting Dandy Pandy's idea or my objection to it. If the former though, I would say that it's not just about switching out gear on units. HQs are an issue. If you want to bring a generic hq, sure you could bring a tooled down version maybe at the smaller points. But what if you are building towards a named character at higher points? Especially one who might not be super-survivable but has other benefits?
I am one of those people building towards a certain list at 1500/1850 point range, and those lists are built around Lias, but bringing him at 500-750 points would gimp my lists at those points. Keeping a random other HQ I don't want at higher points, gimps those builds. Also, it might be fun for some of us either trying out new armies or (like me) returning to the game after a LONG absence, to be able to play around with and try out different units that we might be unsure of at higher point builds.