All the features that I would recommend are already in TaskWarrior. Have you seen/tried it? Maybe you should highlight some of the competitive advantages your app has over it. http://github.com/taskwarrior
t -a whatever the task is without single quotes :) :weekend +++
Another neat thing about this is that it allows you to do stuff on multiple tasks at once. t -d awse,foob #deletes the tasks with those ids
t -t aswe,foob :some-tag :another-tag #adds those two tags on those two tasks
If you know ruby, you can tweak this as you like to make it work with your own special rules, and that's the most important thing to me. No one likes a task manager built by others, everyone has something which they do differently. And because it's built in ruby, I hope this is easier to personalize.