If I was a prophet and had described KDE-1.0 in that announcement, few people really would have been so curious to actually start working on such a huge thing. Instead, we would still discuss wether we should support X at all, or rather start writing our own graphic device driver and toolkit. Especially the quality of the integrated webbrowser still surprises me, given the short development time, its small size and performance. Maybe we could have done the configurable keybindings for both the desktop and the applications ealier. However, these are now available in the KDE-1.1 development tree.
Window managers are applications that are responsible for the window decorations.
That means, the way the titlebar or the frame around a window looks. In addition, some windowmanagers come with some kind of startup menu to launch applications. They have no influence on the graphical interface of applications, though. The old and weird xman utiliy for example is completely the same under fvwm, afterstep or any other window manger. It does neither become nicer nor more userfriendly.