... The primary motivation for using it is that it has as many bugs as original FS2 (none) ...
Retail FS2 has a TON of bugs in it actually. Beyond numerous general code bugs and big code issues with newer computers/OSes, it has some rather bad memory leaks. And we are still finding bugs in the retail code even today. Some of the bugs we can't even fix because it would break compatibility with retail multiplayer or retail missions.
Kazan's FS2NetD code had more than a few bugs in it too, and those have been fixed in SCP, but I don't think that the OEB keeps up with those changes. The server heartbeat issue, along with several other FS2NetD specific packets, is strictly bugs in Kazan's original code. Those packet changes are only to how it communicates with the FS2NetD server though, and not how hosts/clients work together. The FS2NetD server code has also had a significant number of changes to fix bugs there and work better with SCP builds (but not exclude anyone obviously).
There is also always the question that SCP crashes could be caused by OEB and not even be SCP problems. OEB isn't just retail+FS2NetD, Tom has made numerous changes to the code beyond just that. I don't know whether OEB actually has incompatibilities, but they can exist, and I don't think that OEB has the debugging/coding forces behind it that FSO does.
And, as karajorma said, OEB will NOT work with the new PXO code. The choices will be the original retail version, FSO code version > 3.6.9, or the icculus.org version. The retail release will still have compatibility, but the other two code bases would be required at a minimum since the number of new changes to PXO require full cross-platform support.