It's not the program that FTM2012 will see, it's your Family File that FTM2012 will open. You do NOT have to have Version 16 or earlier INSTALLED on your PC. Since FTM2008, if is "sees" a FTW file, Family Tree Maker will make a Back Up, or suggest that you make a back up, of that file, then create a NEW file in the Version of Family Tree Maker that you installed.
"simplified interface"? I don't know what that means. There are some users who would argue that FTM2012 is "simplified". It is a major change from the way you interface with the progam.
FTM2012 looks much like, from what I have seen, it very similar to FTM2011.