It's just that so many four door convertibles have been executed poorly in the past fifty years or so. I know it can be done right aesthetically... It's just that the barriers to doing so today are rather formidable. There are solutions, but each adds considerable complexity to the design. Hence, why so many either only do coupes as convertibles (avoiding the issue altogether), or live with the least common denominator kludges that are conceived for four door convertibles.
A literal, cloth 'ragtop' is out of the question. They always look really, truly, very bad when applied to 'chopped' sedans. So it would have to be a hardtop convertible, and that means a whole lot of weight. Not so bad in a gas guzzler, pretty bad for an EV.
Rear 'suicide' doors are a must, because regular swinging doors just get in the way at the rear. But not the stupid half doors at the back. And hopefully something that doesn't require a front door be opened first.
The B-pillar has to go. But side impact crash regulations have forced some to use a sort of 'basket handle' rollover hoop -- which looks stupid. Maybe a half-height pillar, beside the front seats would do the trick. But even that would seem out of place.