Honestly, daventry, I have no way of answering that--had it never been mentioned, there would be a totally different storyline, at the very least. Had MoE not been the last game we had, I don't know if there would've even been a TSL.
As disappointing as MoE was as a final note in the official series, though, I'm personally kind of glad it happened. Being a part of TSL, this team, going through all of the work and frustration and rejoicing, it's been a life-changing experience for me.