Personally I think the grouping is a benefit, and I agree KnightWRX in that Snow Leopard's all windows was visually a mess. Yes it could allow you to switch to a specific window with a single-click, which was great, but as you opened more windows it took longer to find the one you wanted and click it.
So grouping isn't a bad feature, the problem is that there's no easy way to open a group. What Apple needs to add is a feature whereby clicking grouped windows will switch to the application windows view so you can see all of them. It'd be an extra click, but it'd much cleaner overall and scale better with number of windows.
The absence of minimised windows is
well I dunno about it personally, as if I minimise something then I don't want to see it. Maybe in application view only, but I'd personally rather have something more along the lines of the Windows task-bar preview, but for the minimised windows, as the title of the window isn't always that easy to pick out.
I just want to note that I don't think Apple feedback is a great way to get a feature changed, but if you do do it then you might want to file something on the
Apple Bug Reporter, just send in an enhancement issue for OS X, noting that Mission Control's grouping could be improved. I've already filed one for quicker switching to application view from all windows view, so if anyone else likes it then feel free to post something along those lines, maybe it'll get some attention that way. I just want to warn people away from posting items as bug reports as they may not get attention, since Mission Control does function as expected, it just doesn't fit everyone's use-cases as well Exposé did.