+1
For the love of God make the Steam authentication optional. I'll be the first to admit that it's good for account security, but I do not appreciate being locked out of a subscription based game every time Steam shits the bed- which is often. There are enough security features already that it's downright unnecessary for the 90% of players who aren't falling for every phishing scam whisper they get.
If I had known this would be a problem before I bought the game on Steam I never would have bothered. I would switch to an SE-tied account in a heartbeat if they offered it.