1. You should fully support romaji entry for looking things up. The mechanics of switching input methods on iOS are pretty terrible so it is really inconvenient to have to switch into Japanese input mode. I searched for "hana" but got only 花合わせ and 花を引く as matches -- because those have 'hana' in the English definition string. Searching for はな brought the two obvious matches (花 and 鼻) to the top, but I had to go back and cycle through several other input methods to get to Japanese input mode, which was annoying and took longer than the rest of looking up the word. Some other dictionaries do this, and even sites like Amazon Japan now do this for searches as well -- dealing with input methods is just a hassle in general.
2. The understanding of verb conjugation seems really awesome and jumping between things on a "learning tangent" works really well.
3. You have to sync vocab lists and spaced repetition drill status/progress to the cloud. It's just too useful not to do it -- you want to be able to do that in quick downtime moments from any device. Luckily there are many easy ways to do it nowadays. I don't blame you for shipping without that, though! ;-)
All in all, great start!