Really? More people have downloaded the playtest documents in the first few months than in the entire D&D Next playtest. The surveys are getting something like 40 THOUSAND responses.
Or, to put it in more perspective:
WotC has announced that more people have playtested the first One D&D playtest than the number of people who playtested the entirety of the D&D Next playtest 10 years ago, which led to the release of D&D 5E. The number of people who playtested D&D Next, according to the credits in the 5E...
www.enworld.org
I'm not really sure how much more enthusiastic we could actually be.