I also think M&S should stick to good quality, simple basics. However I can quite clearly remember (15-20 years ago?) when M&S were getting a LOT of stick in the press for doing just that. And being criticised for not providing fashionable clothes for younger customers. M&S was considered 'behind the times'.
That was the start of them completely losing their heads, and getting in person after person to 're-vamp' the clothes section. It has been crap ever since with bizarrely inappropriate necklines, too many shitty patterns, awful frills and flounces, and the sort of naff designs that even Matalan would not stock.
What M&S have utterly failed to do is to promote what they once had, which was a feeling of dependability, of reliability. I used to be able to go there and KNOW that I would find a good jacket in a useful colour, a great wool cardigan, a fitted T-shirt etc, etc. Now I occasionally look, and just despair.
And someone needs to sort out the bloody appalling bra-fitting service. How has that amount of pig-headed wrongness managed to survive??