I tried to keep it dirt-simple as well: just let me add tasks, click a button to start timing and click the button again to stop.
I have a list of things I'd like to add (let people use it without creating an account, tags/categories, mobile support, etc.) but it works well enough for what I use it for now so I haven't gotten back to adding those features yet.
This is where I like Google Play market more, where you don't have to take risks. You can just buy the app, and if you don't like it, you can get a refund. Apple should have done that a long time ago.
Actually though it was an experiment for me using Backbone and Mongo, so I wasn't sure it was even going to hang around very long, but it's been a useful tool for me as it is so I haven't felt the need to make any real changes to it.
Plus at this point, since I haven't promoted it at all I'm the only person who's using it so I'm not super motivated to work on it.