The ESN editor is still there, it's just available at the TM server console instead of through the web app. Basically, TM 3.0 behaves and feels like a half-finished conversion to a web app.
TM3.1 is supposed to be better, (bugfixes,) but you still have to use the windows apps to use the database editor, ESN editor, etc. It's basically an unfinished product.