DOpus Magellan supports both spatial and browser modes, Workbench is only spatial, but you can configure a qualifier key to hold which makes parent window close as you open a drawer.
Ah, that's something at least. But it would be nice if it was like a.. more native work-within-one-window? Maybe it's a hassle to change stuff like that. A button the window to enable it! Or an option in the window-menu, "Use browser mode". Oh well. :p
I guess what I mean is, there's a lot of "smaller things" that can be improved for user experience in handling files in workbench, visually and in functionality.. I mean if you are gonna handle larger amounts of files, you use dopus, filemaster or something instead. At least I do.