There's no doubt this issue is nuanced, and I find it hard to settle on an opinion, but in the end I tend to come down on the side of supporting (and by extension enforcing) bans on burqas and niqabs.
Why?
Because, although it's not straightforward, I consider such things to be more repressive than freedom-enhancing. There's no doubt an argument to the contrary, but I don't think I've heard one I buy into. Whilst I accept that my position would involve restrictions and enforcements on others, I think it would be for the greater good, and more freedom-enhancing, basically, possibly on the basis that more people would be more free, even if some aren't.
The one part of your post I'm not sure I would agree with is your use of the word 'fashion'. That tends to imply free (or freer) choice than I believe generally pertains in this case. It is my understanding that many woman are coerced or pressured into wearing burqas and niqabs, and that is where my concern would be, if it's true. I'm not suggesting that many other items of clothing are not worn because of some sort of pressure too, but I draw a line somewhere in this case.