I had also checked the @retry field in the eventHisto table, but that's always set to 0 as well

Thanks, Kapil.   I had checked that field thinking the same, but doesn't look like it's getting populated in our instance.  Figured it may be recorded in another table

Does anyone know where in Campaign's database I can find how many times an email sent from Message Center was retried before it was successfully sent?    

We're running into the same issue and while I was able to validate your approach works, it creates for a very messy report when looking at daily trends.  Are there plans to include sub-hit segments in Workspace?  Feels like this is a serious miss