Philly is definitely on the lower rung of passes at 34 a game, which would have them tied for 23rd with Tennessee.
One thing to consider is Wentz hasn't had to throw a lot. Game 1, the Eagles went up 22-10 midway in the 3rd and ran most of the time the rest of the way. Game 2, they were up 22-7 late in the 3rd after they had to go a whopping 2 yards for a TD thanks to an interception (TE Burton got that TD). Game 3, they whipped the Steelers to a 34-3 win. Thanks to these lopsided wins, they've been able to run the ball 32 times a game, which ranks 2nd behind Dallas. The defense has looked solid but they're not always going to face Cleveland and Chicago (and I'm sure everyone was surprised by the Steelers outcome). In games that are closer or they are even losing, we'll see Wentz unleash.
That said, I am encouraged that Wentz has shown a consistent willingness to throw to the TE. In those 3 games, he has targeted a TE 8, 8 and 10 times. Ertz was the 30th most targeted player last season on a per game basis and some of that showed Game 1 where Ertz got 7 of those 8 targets. He is a primary option and gets open. The QB is different but I still see him getting 7, maybe 8 targets a game and with an average of 10 to 11 yards per catch, he could be very very solid as a PPR TE.