So BP3's story is all written so we should think of subtitles for it. There is a little gap in that logic though: It is written but we don't know it!
Anyway...
Here are my favourites so far:
Odyssey Into Hell - Okay. Not liking titles with hell I would usually reject this, but that it's a quote from Petrarch from the original FS2 changes that.
Lessons from Infinity - A very fitting name, since we learned lessens from both the Vishnans and the Shivans already.
Shattered Balance - Do I really need to explain this after the events of universal truth? Though I'd suggest making it "The Shattered Balance". Feels more natural as a title to me for some reason... maybe the three letter thing.
While I don't have any suggestions as good as the above I do have some ideas:
"Restoring the Balance" - this one is pretty much just Shattered Balance from another view, so can hardly be called an idea.
"Legacies of Old" or "Ancient Legacies"
"Path to Divinity"
The last two titles play at Humanity becoming the replacements for one member of the triumvirate, be it Shivans, Vishnans or Brahmans.