Larian will probably continue to drabble out bits of new content every few months. The remaining paladin/bard/monk classes are possibilities. It's hard to say how many new areas they will put in the EA without encroaching on Act II. Perhaps new companions? Hard to say about that.
Speaking of new content. It's been almost three months now since that barbarian was patched in. Ought there be another update coming up in May or June?