Fotopolis interviewed Toshiyuki Terada, Product manager of SLR Olympus Planning Department - in a nutshell, Olympus has no plans for now to replace the E-620 since the entry level DSLR segment is now entirely replaced by the PEN system. "High-end" PEN models however, are expected in the future (EP-3?):
“Q: What future for smaller [than the E-5] SLR cameras? Are you going to give them successors?
R: We do not have concrete plans to replace the E-620 and other recent SLRs. The entry level SLR class can be completely replaced by the Pen system in terms of performance.
Q: Is it possible that even more high-end cameras appear in the Pen system, e.g. for the semi-professionals?
R: Of course, one of our goals is to offer the Pen system technology to the world of professionals or very advanced amateurs; as soon as possible to transfer this model from the SLR system to the Pen system.
Q: So can we say that, in some undetermined future, there simply won’t be any [Olympus] SLR anymore?
R: In the future - yes. This is one of our goals but we do not know when this will happen. Until then, we will support the SLR segment because the E-3 users are Olympus’s foundations.”