Thing I hate most about my/all A-bodies

Parts availability
Cost of parts when you can find them
Most aftermarket parts do not fit out of the box
Sheet metal availabilty (I think you can buy an entire '68 Charger now...)
No meaningful support from Mopar (compare to Chevrolet or Ford), I think I can add fuel injection to my 440 for about the cost of a fuel injected crate motor from Chevrolet.
Almost all trim, lights, and bezels are one year only
Small bolt pattern (changed)
9" drums (changed)
Can not interchange small block / big block transmissions, mounts etc.
Anmeter (removed)

I think most of these - and others I can think of have already been covered.