Currently got a williams powered mk1 already wouldnt want to use it as a daily really
Not as comfy, no aircon, they are generally likely to be rusty, brakes arent very good (well mine are, but standards arent)
Just generally not as good daily driver as a 172
I also have a redtopped corsa on bike bodies currently anyway, but its as per the williams really, not as pleasant day to day, seats not as nice, no aircon, not really a sassy/chic girly runabout for the mrs either TBH.
Also they dont handle anywhere near as well, mines on coilovers, uprated ARB, modified geometry etc, and still nowhere near as nice handling as the 172 with just a set of springs
Less power, not comfy, generally rusty, no aircon
Rubbish daily especially on the motorway, and nowhere to put track tyres
slow, dont handle, rubbish on fuel, all rotten unless you spend a fortune or get very lucky, no aircon
Much dearer on tyre and fuel (unless a derv), handling not great generally either unless an M model or modified, and then its a bit of a money pit
plenty other stuff really. granted most havent got aircon/cc, but your old skool so that shouldnt be a problem.
TBH everything you listed just falls massively short of the 172 for our requirements even if you take the aircon issue away, and then really only a williams comes close and they're still nowhere near as pleasant on the motorway etc.
Definately confident we made the right choice, all the suggestions you make just re-enforce that belief TBH!