I'd say that $700 is pretty reasonable for the current market.

I'm always tempted to expect the $199 off season r/t to London or $400 year round fares to Paris that were common 5 years ago, but it's just not there anymore.

You've definitely found the best cheapos, I've seen lately with the east coast to Germany fares.

Maybe if you're willing to add an LCC (check whichbudget) and/or a bus or train ride, you could do better, but it'll cost you in term of hassle and time and schlep.

Edited to add:Welcome to Flyertalk!