Actually I disagree to an extent. The mere fact that certain types of website will have specific extensions leads to easier categorisation which has the potential to have a bg impact on search.
Categorisaton also makes it easer for politicians to enforce certain restrictions on search providers.
And don't think that can't happen/won't happen. We've already seen the US Government confiscate .com domains that threatened the viability of US businesses to compete in their home market, simply by issuing instructions to ICANN who handed them over.
There are other angles on this too, more consumer oriented. It obviously remains to be seen just what impact this has but I really do thnk it is a major development that sharp minds mght exploit, for better or for worse.
I'm no sharp mind but one thing that immediately occurred. If you could just type widgets into your address bar, the fact that a lot of widget sites will have the .widgets extension. Categoriation has the ability to simplify search algos and consequently level the playing field.
It needs to be properly controlled, gaming needs to be considered of course, but it could mean a lot more competition for Google if it's done right.