After playing the latest patch a good while last night, the main thing I currently find lacking is monster and spell variety. As you say you say though more will be added once the main systems are in place, so figured there wasn't much point in mentioning. However, a lot of the spell ideas I had sounded like things that would be added with what I thought would be glyphs at the time, but I don't see mention of that here? Things like cone spells, exploding spells, homing spells, beam spells, ground only spells (like a wave of flame), more variety in shield spells etc etc.
If you've played a game called Magicka - it has a wide variety of spells and it allows for many different approaches to every situation, which stopped it from getting boring quickly and left a lot of things to discover. Combinations of spells that work well together (especially synergize well or literally combine) made co-op especially good too