I've been backpacking pretty regularly for the last 35 years, living up to a month on the trail (just so you have some background on the random internet guy). I've used a lot of packs over the years, going all the way back to the Lowe Contour IV (other old fellas will smile when they see that name).
I decided a few years back to get the best I could afford as I get up there in years, so I ordered 6 different backpacks, including Mystery Ranch, Stone Glacier, Osprey, Sitka, Erbelstock, and Exo. As always, the Rokslide folks knew what they were talking about, and the Exo was by far my favorite. (I know Stone Glacier has a lot of fans, but I found it to be a noisy ski pack without a lot of pockets). I returned all but the Exo and the Osprey, the latter I backpacked with for a few summers, but ultimately sold - it squeaked constantly.
I've been running the Exo K3 for the last 3 years and love it. My understanding is the K4 is even better.
Two tricks I've learned hunting with the Exo - the Kifaru Gun Bearer is far and away my favorite gun tote. I don't use a rifle sling, and this sucker is the fastest way to bring my gun into shooting position. Fits great on the Exo. Second - in addition to your game bags, carry a construction trash bag for the load panel. I've spent too much time scrubbing blood out of a pack, and a construction bag would have saved from a lot of blood.
Good luck in your search!