An awsome feature would be an edition mode where there is no predefined time signature. That is: you put the notes one after another, then you add a bar and it automatically computes the time signature of the measure.
Sometimes, you have the entire riff in your mind, but you don't know exactly how you want it to be split into measures. The only way to deal with that for now is a try and error approach which is very annoying (due to the fact that you have to rewritte all if you did a single miss).