What you describe "might" work, but I think it would be most confusing.
Most of us encountered Power PC programs that would not run under OS X 10.7. Most software developers have provided updates by now. I only had one issue - Office 2004 needed to be updated to Office 2011. I abandoned the Microsoft stuff and switched to iWork (less expensive and compatible).
Everything new will be written to run under OS X 10.7. Eventually you would find yourself in a dead end street with obsolete software.
End of gratuitious advice