The current rumor and mind you it is just that a rumor is that the Hero will be getting the update in mid March.  Now is that because of Sprint or HTC or what.  Might Verizon's Eris get it sooner.  It is possible if HTC has completed the update and the issue is with Sprint then the timeline is based on the carrier's testing and having the system set up and ready for an OTA of that size. 

It stands to reason that HTC might be part of the slow down.  They did have the software first but they were focused on getting the N1 out and then all the issues that came up that needed an update to fix.  they have been a bit preoccupied lately so it might be that it took them a minute to get the update for the hero based phones situated.