Casino Royale really could have lost all three of its major action set pieces and been just fine. The parkour chase just feels like a slightly more refined holdover from the Brosnan Era, the Miami sequence just goes on far too long, and the sinking house stuff at the end of the film completely destroys the impact of Vesper's death. IMO, the majority of what is wrong with Casino Royale stems from the action set pieces. I think that, if we could go back and tweak CR, that overhauling the action sequences and going with action scenes that are more in the style of those found in Skyfall or Casino Royale's own stairwell fight, that the film would be drastically improved.
I tend to agree, though I do feel that the parkour chase was part of an effective introduction for DC, though typing that, I have to immediately disagree with myself and say that the PTS is as good an introduction as SC's at the bacarat table in DN. The Miami sequence is too long - at the time I remember Campbell "reassuring" fans that the film would have a big explosion; not sure this fan feels the need for the big one in every Bond, but there you go. The sinking house is a bridge too far, so to speak, and like the airport chase feels obliged rather than inspired.
Would hate to lose the parkour chase though - IMHO it's up there with the best set-pieces in the franchise's history. What those are, well, let the debate begin....