And even then, the activation keyword is likely to be whatever Apple says. Similar logic as 3rd party keyboards, don't want user input to get stuck on even merely potentially untrustworthy or buggy code.
I guess this won't change, because it is probably for legal reasons, to avoid being sued by some "I just dried my cat in the microwave" style genius after making a car accident (unrelated to Siri, but trying to shift the blame).
Adding support for smaller languages would be nice actually. When its reading out of Hungarian messages loud it sounds incredibly retarded. I always have a great time listening to those and trying to guess the message. :) It would be nice if I could send a message to my significant other about being stuck in traffic in Hungarian. (the iPhone keyboard already does pretty decent voice recognition in the language)