All of these recent picture are making me crave a Muse II, even though I swore to myself I'd get a messenger type bag as my next YSL. Either besace or rive gauche. Le siigh.
^I've been using my Muse Two exclusively for a couple of months now, and the top closure works fine for me. In fact, there are many times I don't bother with the little button closures on the straps and just have the main latch keeping the bag closed. I carry my essentials (phone, wallet, keys) in the back exterior pocket, though, so I'm not constantly opening and closing the flap.