2 RIM additions that would make the experience much better.
#1 You know when you are adding a new task? It would be nice if you didn't have to go back to a few earlier screens just to make sure exactly what the time and date is. It would help if it was right there for us to see.
#2 I feel this one is a biggy. Inside the Calendar they should give users the ability to scan specific months whenever they want and have the app turn up what, if any, events are planned for that entire month. Going a step further, it would be cool if it were possible to have it scan multiple months at once for all events that are taking place between now and then.
This way you don't have to painstakingly search through the agenda for a specific month to see whether something is planned or to find that person's birthday you can't remember off the top of your head so you have to search through your phone to find it.
Those are 2 very simple additions that I think would help a great deal. They should also be relatively simple to add.