The problem is that m+s try to cater for everyone...and appeal to no one.
They want:
Autograph - sophisticated working women. Matching suits, shell tops and 'key pieces' in natural fibers. Top end market with whistles cos etc
Limited: younger audience, more fashion forward. Shorter skirts, interesting but wearable shapes.
What you get is a mishmash of copies, not done well. Totally missing the style element. The boden tweed dress is stylish because of the fabric. Change it to red tartan and you loose all the style.