I expect Hellickson to cool off, while he's gotten better with the command of his secondary pitches, and the cutter has become his slider, he's still limited by a 89-90 MPH FB. Which also makes him vulnerable to the 3rd time through the lineup, they get to time him and he can't afford any fatigue that would reduce velocity or command - so I see him as a 6 inning pitcher. Still a solid #3, but that's his ceiling.
Altherr, Kendrick, Saunders, Nava and Stassi have given the Phililes far better production from the corner OF spots, which has changed this from a 5-6 man to a full lineup. Just as important, they have a full bench this season, which allows them to matchup players and to rest (Blanco for Hernandez) players.
I also think Stairs has helped, you see them with a lot of tough ABs, which drives up pitch counts and explains why they have come back so often, they get to the starter the 2nd or third time through the lineup and get middle relievers into games. The last few games, a lot of the outs have been "smoked," which tells me that some hitters that were struggling are getting close to having their timing down.