I think one thing that he has been very good at is making sure that any new talent that shows up has a clear-cut gimmick and a real purpose for being on the show. It used to happen with almost everyone that debuted, but for a long time, they were randomly debuting lots of new people with no set-up and with no particular reason for anyone to give a fukk. But over the last couple years, there hasn't been any massive influx of new people just popping up and no one knowing who the fukk they or their characters were. We know Cesaro, we know Ryback, we know Sandow, the Shield, even fukkin' Fandango and Brad Maddox- because they all have an identity. It's been said that he's specifically ordered this to happen, and not to debut anyone unless they have a real character and a general idea of what they want to do with them, and it shows.
And of course it hasn't been perfect. Sin Cara isn't the big hype he was promoted to be, and the Kharma situation didn't pan out (I can't say "flopped" because it's not like she got a push and it didn't get over- she got pregnant, had to take leave, and had a traumatic experience- not the same thing). Yeah, the Divas division has dwindled but that shyt ain't been poppin' since like '07... and they don't have a Trish/Lita/Mickie on that roster now, so I'm glad it's being de-emphasized. The tag team situation I wish would get back on track... they have enough people to revamp it, but the attempts have been half-hearted at best. I don't think it'll ever get like it was in the late-80s/early-90s or the early-2000s, but it's worth a shot.
All in all, I think he's made some good decisions over the last couple years. There's not a bunch of non-descript muhfukkas clogging the roster (2006 shyt), there's not a bunch of models who didn't even wanna wrestle before being offered the job (Johnny shyt), and most of the new additions have freshened up the show. HHH is also somewhat of an old school-minded/wrestling historian type guy so I think there's still some improvement to come.