Perhaps he applies different standards to the sleeves of his solo albums than Roxy ones? The "In Your Mind" cover was pretty ropey, "Bride Stripped Bare" and "Taxi" can't have taken that long to put together. The"Mamouna" cover was ok but then someone else had already done the painting for him

"Boys and Girls" was quite stylish in a "9 1/2 weeks" sort of way.
Maybe after so many years working on some of these albums he was so desperate to finally get them released that the sleeves became of lesser importance, unlike in the early 70s. By 2002 Simon Puxley was no longer around to add his thoughts either.