The basic idea behind the shuttle was that this approach is teribly wasteful - because it is.
The shuttle is also wasteful, in different ways. The technology hasn't progressed to take advantage of a re-useable system. They still treat every launch like a one-time, special event.
That the shuttle has failed to meet its promise doesn't mean reusable vehicles are a bad idea. It can just as easily be used as an indictment of the NASA way of doing things.
But again, I'm not necessarily against a capsule. I'm just not impressed by the thinking that came up with the idea. It sounds more like "Let's do what we know NASA is (or used to be) good at" rather than, "We need fresh new ideas to jump-start this failing space program."
Is it truly more cost effective to reuse the SRBs from the shuttle, combined with the cost of inspection and refurbishment of each shuttle, plus the cost of a new external fuel tank (the only portion that does not get reused)?
How much usefull payload could the two shuttle SRB's lift if they weren't hauling the external fuel tank, the wings, tail, landing gear, and other parts of the shuttle that are used only for a very small portion of the entire mission?
What if we strapped a couple of reusable SRBs onto the side of a single, one-time-use cargo pod, with reusable crew compartment on top, and used that to haul stuff into space. After all, just as in modern aircraft, the "people pod" makes up a disproportinate amount of weight, compared to it's volume, and the greatest amount of technology and complexity of a spacecraft revolves around keeping the carbon based lifeforms alive.