But I wonder how useful it would be in the UK with our weather? I can think of no more than a handful of days in the last, say, 6 months when it would have been sensible to plan a x-country VFR flight at 3000'.
IO was obviously up before me
PotKettle...'s idea is a brilliant idea, and would work well in the UK. The US doesn't have some magical weather phenomina, parts may have better weather like Arizona for example but even that is not always true. Try meating a thunderstorm line in the desert in the middle of summer when you are struggling to stay at altitude due to density anyway
Even the LA basin has freezing levels down to 4000' regularly in the winter and lots of visible moisture, and with MEA's 6000-11000 in the area icing can be a real factor.
Anyway, I'd rip up the airspace and give Class C to all the major airports, but limit the top of the cake to 5500 AGL then have class E until the upper airspace. Less major airports (The Exeter and Plymouth types) I'd drop a Mode C vale around. The major change though would be to reclassify airwyas.....why do they need to be A?