I actually still like this idea. I'm more against the idea of Leitrim, Sorangath, etc. than this.
Basically, I'm taking Alric's line: "Balor has been killed before" literally since I don't think Connacht was ever killed. He either died or wandered off into the East to return as Balor.
There's more to it that I can explain, but not now... school beckons :(