Personally, I don't look to the iPad app to replace my laptop for serious study, but I use it primarily to read my books and take a few notes. I use Logos iPad to do any lengthy reading and as my Bible of choice when attending a Bible study or conference.
The # 1 thing I would like to see is the ability to read any and every book in my library - including PBB books in the near future. I realize this is largely a matter of copyright permission from publishers. I hope Logos will continue to work towards gaining the needed copyright permissions so that we can read our entire libraries. That would be the biggest improvement possible for me.