I'm assuming the brakes are adjusted properly.)
Tektro Oryx Cantilevers, Silver -> the stock pads are not so good in the wet. Change the brake pads to something like the Koolstop salmons.
Shimano Tiagra, 3 x 9 STI -> I have these on my touring bike and I like them a lot. What are you comparing them to? And what are the numbers on the cassette and crank you were using with what you are comparing them to?
The Cassarole is spec'd with a 12-25 cassette, which should not be slow to shift (wider cassettes are a bit slower).
The crank is 26-36-48T, which could be slower (compared to a standard road double 42/39-52 or
any double).
http://salsacycles.com/bikes/casseroll/