I downloaded your app today and rooted around in it. Good start.
If I'm using a brew-day utility, it has to have mash calculations (volumes and temperatures), and automatic timers/alarms for hop and other kettle additions. Also must add "other ingredients", and make it customizable so that users can add whatever...fruit, spices, etc. I also particularly like the very easy sharing of recipes from the BeerSmith Desktop to the mobile app using BeerSmith's Cloud storage.
In all of the brewing software I have used, the thing which developers seem to love to include but which I do not find useful at all, is an ingredient inventory function. I buy stuff all the time, and I gave it a good try in the software I used long ago, to enter stuff as I bought it. But it was honestly more of a PITA than a useful tool to me to keep up with the inventory. I'm guessing maybe some folks like that function, though.
I do not have software development knowledge or skills, so I'm sure this is quite a project. Some years ago I built a relational brewing database using my Palm TX and an off-the-shelf database called SmartList To Go. Neither of them have been available commercially for years now, but I still use it sometimes. For the technology, it's pretty versatile, has very accurate mash and water use calculators, and the built-in timers are the bomb. But it's main limitation is the number of malts, sugars, and hops I can use in a recipe (3 or 4 of each) because I ran out of available fields in SmartList.
Good luck with your project.