My opinion :
Is the American Mafia still strong in New York in sophisticated criminal activities ?

Yes, in those fields they even have a monopoly.

Are they still the top in drug trafficking or extortion in NYC ?

No, they have received far too much competition in these fields. Russians, Albanians, Chinese, Dominicans, Puerto Ricans, African-Americans, Jamaicans, Koreans,...have agressively muscled in on these activities.

The American Mafia will still be strong in NYC for a long time, but in Detroit, Pennsylvania, New Jersey, Tampa,...they are dying out. Sad but true.
In the West Coast and the South organized crime is controlled by Mexicans, Chicanos and other Central Americans, Rednecks, African-Americans, Chinese, Southeast Asians and Armenians. The influence the Mafia has there, is neglible.
Florida ? It's all Cuban, Colombian, Haitian and Redneck stuff going on down those parts.
The Patriarca family used to be big in New England, but nowadays the Irish are still stronger in that area ( I'm sure ).

Some people may find this highly unpleasant, but really the only area where the Italian-American mafia still has a lot of influence is the NYC area.