The reasons for this are currently unknown; I was going to e-mail VIZ for comment, but I saw that they had declinded to comment for ANN, so I elected not to bother them this time around.
If I had to hazard a guess, I would say that the economy being what it is, VIZ was probably becoming less excited to jump forward into the financially risky waters of OEL, and when things didn't go smoothly (perhaps due to Weidenbaum's departure? We don't know what order things happened in) they put the project on hold.
But that is just my entirely uninformed guess. Sad nonetheless; I was looking forward to seeing what they did.