Olympus has already stated that the EM-5 is not their pro m4/3 model, so....
I would assume that the eventual replacement for the regular 4/3 will come about in the following way:
1. Olympus will introduce an EM-50 which will replace the E-30 for enthusiasts - essentially a cut-down EM-5 without weather sealing and fewer control points.
2. The EP-3 line will inherit the new sensor and be the 'prosumer PEN' while the EM-1 line will continue for P&S upgraders as a stripped-down body. The E-PL line will be discontinued.
3. Olympus will introduce and E-7 with much hype leading to disappointment with much of the guts of the E-M5. This will require minimal R&D as they'll keep the same E-5 body/chassis. This will be the final curtain of the 4/3 line.
4. They will then introduce a "pro" EM-7 (with the same senor, but *tweeked* - lol) which will have improvements for AF with regular 4/3 lenses. This model will also have some form of electronic focus peaking.
Including the E-5, Olympus now produce 5 bodies. I believe the 5 bodies in production this time next year will be:
Meanwhile, Panasonic will have introduced their latest generation 4/3 chip via the GH3 and Olympus users will be lamenting the old-tech of their 16mp chips as Olympus recycle the technology in *tweeked* form into their bodies for the next 4 years
As for lenses, Once the two Olly primes and the two Panny fast zooms are released this year, I don't see how more lenses will be needed to be released (aside from updates / mark II lenses). For those in need of fast zooms, the current 4/3 line-up has excellent examples which when coupled with improved AF on m4/3 and the addition of a grip will prove sufficient.