Replace HTC Sense "recent apps" by stock ICS
To answer your question about launchers:

Yes, they are like explorer.exe on Windows. Most launchers will replace the home screens and app-launching window. Some may even affect the app-switching, but you might have to play around with them.

A short list (note: not complete) of Alternative Launcher apps:


Nova Launcher
ADWLauncher / ADWLauncher EX (Paid)
Go Launcher EX
LauncherPro / LauncherPro Plus Unlocker (Paid)


Looking at the above apps you can see how they change the look-and-feel of the bulk of Android's UI.

I have tried most of the above, and each have extensive options and tweaking abilities to get your home screens and app launchers to look the way you want them.