Did canon not also do it from FD to EF?? I won't pretend to know what Olympus will do but if a significant advantage exists then they should probably take it. But I do agree that maintaining backward compatibility is very important and the technology probably exists now to make that a viable option. Every rumour says that modular is coming (not necessary the e3 replacement) and how they implement the modularity will be very interesting so even with a significant change, I doubt the nice existing 4/3 lens will become obsolete.