What's with the "asset" in Paris who went to Bourne's apt. to kill him? Did he really have to swing into the frickin' apt through a glass window with his machine gun blazing? I mean, really -- he already popped the old lady who let Bourne intot the building --- he couldn't be any stealthier than that? It doesn't ring true somehow.
My take on it Treadstone started with Bourne, but then started looking further afield for "cheaper" agents to use in Europe.
Guys like the Professor and Jarda seem to be confident in themselves, so have probably been involved with their nations security service at some point (maybe due to the end of the Cold War and being surplus to requirements)
This is still a lot of money that has to be kept off the books, but at the same time is used for the "greater good".... and probably the cheaper they went the less important looks and tactics became, as out of the whole trilogy, Castel really does come across as the poorest and most slopping agent Treadstone have..... so probably his methods were useful, but he was a little to trigger happy to send on important missions (after all Conklin said send "all" the agents in to get Bourne.....)
Yes, Treadstone made a stupid mistake. There presumably was some surveillance of Jason's apartment, but even though Castel would have pretty well known what to expect, he did unnecessarily rush in, blazing. He's obviously just as violently capable as Bourne, but not nearly as smart as Bourne.
_____
I don't have a dog. And furthermore, my dog doesn't bite. And furthermore, you provoked him.