Looking at the race as a whole, there were several things to learn for all the leading contenders (and the others), particularly from the mistakes by leading riders and teams which show that no-one is the dominant favourite for the Tour.
1. Sky have the strongest squad. However, they didn't want to concentrate on keeping the jersey through all the stages, but they were forced to do so - rather like being forced into leading out in a track sprint. That shows that for all a team's power and ability to control any particular stage, it does not mean that they can control the whole race. Sky's power riding can also lend itself to being hijacked by a single rider without at team as Contador showed.
2. Tinkoff-Saxo had the strongest rider in Contador, but they also ended up unexpectedly in the lead and then didn't seem to know what to do about it on the final day, possibly because the team they deployed wasn't the strongest one and wasn't geared to defending a lead. They also (as per the discussion above) made a tactical mistake in letting a determined break containing several highly-placed riders get too far ahead and for all that Contador was the strongest, he couldn't pull them back on his own when many other teams (including Sky) were not prepared to help.
3. Of course, Contador, Froome and Nibali are far from done, but we're entering a new era in pro-cycling right now with some fantastic riders who are going to be competing for the top stage races over the next 10 years: Aru, Arredondo, Bardet, the Henao cousins, Kelderman, the Quintanas, Sagan, the Yates Brothers - and there and more than a few others who are yet to show their best like Alaphilippe and a whole bunch of other Colombians, not to mention the Eritreans who are set to be the next Colombians. It's an exciting time.
4. Finally, to add to the excitement, this race showed that even in the age of race radios and careful planning, opportunism and determination can still win stage races and turn what appear to be foregone conclusions on their heads. Attacking riding can win not just stages but whole races and that's a very good thing.