So--and this theory has been said already in this thread--new Sonic, revamps the old one and gives it to River Song. Ok, super.
Except Matt Smith is 26 and Alex Kingston (River Song) is 46. Yea the Doctor is 900~, but still...that's weird. I just can't see proper chemistry between them for the River Song story arc to flesh out.
BUT- on the topic at hand, the new SS. I like it. It's different, but so is the Doctor. I'm sure it'll work.
The funniest thing would be if this turned out to not be the Sonic Screwdriver. Perhaps he got his laser spanner back! :lol