1-2-3-4 is just Expose style window management. That's something we've wanted to do for awhile, but is more a WM thing. We would not however use the Alt-Tab keystroke by default because it serves a different purpose. Expose is for mouse driven input typically. Alt-Tab is for keyboard selection.
1-2-3a-4a is mostly there already with active vs inactive window styling. That's really up to the theme though.