I use Training Peaks with my athletes, both WKO+ and also their online interface software, which acts as a great communication tool between them and I. One of the best charts for tracking how the season went, can be found in the online software of Training Peaks, called the Critical Power Report.
This chart illustrates some great data, to assess the season and how the training went. You can review the year according to the annual training plan and the different periods of training, such as Base 1 or Build 1, etc.
If you click on the chart to enlarge it, you can see this athlete had their best power performances of the entire season over 60, 90 and 180 mins on November 23rd. That was Ironman Arizona, which helps illustrate he reached a bike fitness peak on race day. I normally don't care if that is the best value on race day, since they still have to run after the bike, but you want to see the peak values still to be similar to the raceday performance.
You can also see that most of the shorter time CP values happened much earlier, which shows how the training focus changed over time to reach the more important values for Ironman, (CP60-180), later in the year and closer to the Ironman event.
I even highlighted the key things I saw, which was the pattern of improvement over the different periods of training for CP90 and CP180. It wasn't always an improvement, but in general the trend went up, which is what we want to see.
Just another example of how technology can give us feedback to see how the training response is for the athlete. As a coach, this information is invaluable.