I had a quick look around but didn't see this mentioned anywhere.
I'm not even sure if I think this is a good idea but just wanted to throw it out there, was a shared skill tree contemplated? I.E. one that every Demigod has access to. I noticed Enhanced Attributes is the same for each Demigod, if it stayed that way it could be migrated over to the new tree and would make room for another Demigod specific skill line. Some other stuff could be added to the shared skill tree like weak auras, static damage increases, reduced rez timer, static speed increases, gold % increases, etc.
Let me know what you think, tell me if it sucks?