There are several really basic principles in User Interface Design, and Considering how badly Microsoft violated many of them, they either didn't have an Interface Designer on their team, or if they did have one they either didn't pay attention to him, or he only addressed very specific issues and left implementation of his suggestions completely open for doing wrong
One of the most trivial ideas in UID is the following:
What's the most important button in Windows 95? The Start Button, of course. Where is the Start button? In a corner of the screen, thus up against TWO sides of the screen. Sounds great so far, right? Try overshooting the button and then click. Nothing happens. The geniuses at Microsoft decided, assumably for aesthetic reasons, to add about 2 pixels of space on the sides of the button, only active for the task bar. Thus the most important button in Windows 95 is just the size that they made it, and the user has to aim just as carefully as ever. In fact it's usually even smaller than the application listings on the task bar.
Have you ever placed the taskbar on the side of the screen? Resize it. If you make it smaller, of course the Start Button gets smaller. If you make it larger, the Start button stays the same size, rather than taking advantage of the space.
positive: can aslways find starting point
Taskbar: Unreasonable space usage on side with unreadable results, including the clock.. Button always at top (or left) My version moves icons permanently.
Tray: Clock takes up almost twice as much space as it needs to.
Menu: Gets big with installations.. low end user doesn't know how to rearrange it. If it doesn't get big, it gets deep, taking the entire screen, and a lot of travel to find your program. Harder to hit items than an icon.. lots of horizontal space, but we're moving vertically and that space is using small icons ALWAYS even though you can set main menu to large ones... Sub menus use a combo "folder/group" icon which is ugly and makes little to no sense.
positive: No double-clicking as they wanted, pauses long enough before opening submenus to prevent mistakes and flashing submenus
Docs menu: ALPHABETICAL ORDER! for RECENTLY USED docs.
positive: global vs. local. Allows "document-centered" approach.. also "new" menu does that.
scrollbars: Not globally changed to prop. Senstivity still there.
positive: Finally are proportional.. like Amiga has always been. Not AS sensitive as before.