The history of Windows NT's GUI:
Windows NT 3.1:
USER32.DLL (client to server call) USERSRV.DLL
GDI32.DLL (client to server call) GDISRV.DLL
Note: This was a very clean system design, managable and secure. It was very slow.
Windows NT 3.5:
USER32.DLL (client to server call) WINSRV.DLL
GDI32.DLL (client to server call) WINSRV.DLL
Note: One server DLL, faster, messier and secure. It was still slow.
Windows NT 4:
USER32.DLL (user mode to kernel mode call) WIN32K.SYS
GDI32.DLL (user mode to kernel mode call) WIN32K.SYS
Note: One kernel DLL. Very fast. Messy. And very dangerous, as one mistake will lead to BSOD crash.
Windows XP:
USER32.DLL (user mode to kernel mode call) WIN32K.SYS (kernel mode to user mode) UXTHEME.DLL
GDI32.DLL (user mode to kernel mode call) WIN32K.SYS
Note: Themes were added, which would duplicate alot of the GUI code back to the user mode CPU side (like scroll bar calculations), as well as add extra calls. USER32.DLL calls down to the kernel mode WIN32K.SYS which calls back to the user mode UXTHEME.DLL (as part of a hidden hook interface) which calls GDI32.DLL which calls down to the kernel mode WIN32K.SYS.
Microsoft has told their userbase that Windows 8 doesn't have the classic GUI anymore. But if you look at this history, where the core GUI was moved into a fragile kernel driver that can crash your PC at any single mistake, and tested for 16 years without any major modification, you cannot trust it to be removed or replaced.
Instead, you get UXTHEME.DLL and DWM.EXE both trying to emulate a functional window GUI, where the real GUI is bypassed by force. Remember that DWM.EXE calls down to the kenel through NT port, and UXTHEME.DLL calls down to the kernel through USER32.DLL's NtUser syscalls. The mess to just draw the simple square window is extreme if compared to Windows NT 3.1.
It is one thing to have Aero glass, but with just simple square flat colored (not even gradient caption bars) windows, then Windows 8 has really taken the wrong turn.
Don't forget that what you see in Windows 8 is a skinned window, and not the real thing, and that it is contained as a 3D primitive. The 3D primitive makes the real drawing of the window slow updated, and the real drawing is done by UXTHEME.DLL, which interpret windows wrong compared to the real GUI that is still functional and availabe in the kernel driver WIN32K.SYS. Just see how the scroll bars don't follow the dragged windows when DWM is running (when title bar is skinned).
I support the original GUI. And if the original needs to be replaced, it should not be done poorly (like adding layers). If Windows NT 3.1 was made today, it would be faster than Windows 8, better managable, and portable.
