The Space Shuttle was a political football whose design was dictated by the whims of Congress and the meddling of the military first, and by engineering second.

The Shuttle was required to be reusable as a political goal. However, it was not given the funding it needed to actually accomplish it in any reasonable fashion.

The Air Force put some tough requirements on it, such as the requirement for enough cross-range capability when landing to be able to launch into a polar orbit from Vandenberg, deploy a satellite, and land back one orbit later. This is purely a wartime requirement. No peacetime mission needs this. This required much bigger wings (and thus much more weight), even though the Shuttle never once launched out of Vandenberg, let alone on one of these crazy single-orbit missions.

Politics screwed up other stuff too. The solid rocket boosters, for example, were manufactured on the other side of the country, largely because of Congressional pork. The long and difficult transport process required the boosters to be built segmented, and that design directly lead to the loss oF Challenger.

Similarly, budget constraints dictated the cheaper SRB-plus-external-tank design rather than a more sophisticated and more reusable (and more expensive) reusable booster. This design directly lead to the loss of Columbia.

The net result was that the Shuttle had a very narrow engineering margin. The SSMEs are engineering marvels in terms of how light they are and how much power they put out. But putting out a lot of power for little weight is a really bad plan for something you want to reuse. Reusability means robustness, and robustness means extra weight and less power.

The Shuttle is what you get when you say, "How much will it cost for a reusable launch system? $10 billion? Too much, we'll give you $5 billion." (Numbers in the ballpark but mostly made up for illustration.)

On the other hand, the Falcon 9R is what you get when a for-profit space launch company wants to make more money. It's not a prestige project, it's not a political project, it's not a military project dictated by thoughts of all-out war with the USSR, it's not subject to Presidential grandstanding or Congressional pork. It's just a bunch of smart people thinking of ways to save their customers money and turn a better profit while doing it.

The Shuttle was an extremely ambitious design that did everything differently. Ultimately, everything was too ambitious to be reusable.

Falcon 9R, on the other hand, is deeply unambitious. The rocket is a pretty standard design. They don't even try to use liquid hydrogen for any stage, even though it's theoretically more efficient, instead favoring easier-to-handle kerosene. Their rocket engines are high performance but not on the bleeding edge. And when they decided to go for reusability, instead of building a whole new system with wings and ceramic tiles and all sorts of other extreme innovations, they just said, let's slap some legs on the first stage and give it some extra fuel. It's a completely different approach that pretty much only shares the word "reusable".

I don't think the Shuttle really has many lessons to offer when evaluating the potential of Falcon 9R.