the last big-name international player the sox signed was dice-k. in the meantime we've seen kuroda, uehara, darvish, cespedes, iwakuma, chapman, puig, tanaka, etc come in from japan and cuba, all of them studs, and the sox didn't get any of them.
seems like the sox got cold feet after theo overrated dice-k. a lot of the fans also seemed to be convinced after dice-k that japanese players can't be good here, though a quick google search for scouting videos could show anyone that darvish, tanaka, etc have way better stuff than dice-k ever did. the sox not getting any of those guys really put us at a disadvantage IMO, not only are those guys elite, but every player mentioned above was a bargain at the prices for which they were signed. and after each success, the market gets higher for these guys.
i really, really hope castillo works out, and the sox are not just jumping on the bandwagon at the wrong time because they recognized that they screwed up by not going harder after these other international pros. the guy's height worries me a little bit at 5'9". don't want to see the sox get scared off again if castillo busts, though.