There currently is no plans for a mobile app, but there are plans to improve the mobile experience.
What parts of updating your lineup on other platforms was easier than Ottoneu? Were they because of the app, or because of the mobile web experience on the Ottoneu site? I think mobile lineup setting has improved for Ottoneu, but I am certain there are plenty of more improvements that can be made.
The main reasons there are no plans to create a mobile app is the amount of money it would cost and the requirement to maintain multiple codebases, instead of the one codebase currently powering Ottoneu. We're a single-person (me!) shop, so maintaining separate iOS, Android, and web experiences is currently too much for me, especially given how quickly I try to move to add features and fix bugs.
Perhaps if Ottoneu grows more, this can be revisited, but I still think 90% of the gap between the Ottoneu experience and Yahoo can be bridged by improvements to the existing web platform.