I can not decide what to make of Happ so far.
The real good news is that his swinging strike % is way up to 14.3% (9.4%, 9.6% last two years) and his contact rate is way down to 68.4% (80.1%, 79.5% the last two years). Both of these two things are very good and at first glance start to justify the amazing K% that he has generated to start the season (32.0%)
However, I can't really identify exactly what he is doing differently. When I look at his page on Brooks Baseball I don't see anything notably different. Velocity is in a similar range that it has been recently and nothing else jumps out either to my amateur eye.
In addition, when he does get hit, he is getting hit very hard. The average exit velocity on balls in play against him is 92.5 MPH which is well up from previous season (85.6, 88.7 last two seasons).
My instinct, unfortunately, is that perhaps Happ's early season strikeout boost has more to do with the teams that he has played (White Sox, Orioles, Royals last three outings) than it does with a change in any underlying skills. That doesn't mean he is not still a useful player, but I think the strikeouts may come back down to earth and Happ will look a lot like he has in previous seasons.