Well, if you are asking for a wish list...
Make the software web-based, that way you can upload your training data to a server (website) and have it logged, processed and displayed. It would be really nice for users to be able to compare their own training programs and performance with other users who have similar vitals and goals. Also, it is good to be able to enter the info in different ways such as uploads from instrumentation or simple web-forms.
I am using the (flash) web-based training log on nike.com. It is nice, but does not allow you to compare and share info with other users. I believe that some weight-loss targeted sites do that, but they are lacking in the training log department.
Another cool thing about the nike training log is that you can add a goal-directed schedule to your "training calendar" (for example, complete a marathon in 3:30), that way you have clear goals to meet for every workout and you don't overdo it.