Scott,
When you say getting them directly off your back, will you be able to take the whole pack off or you need just the sticks to come off?
Because the one nice thing about the shoulder straps is they are quick release. Pull up on the little tab and it disconnects. So you don't even have to slide your arm out. Undo one side, swing the pack around take out your sticks, reclip the shoulder strap release and put the pack back on.
Obviously you'll need to silence all the plastic in the back of this thing if you're strapping stuff directly to it. My thinking is to either make a fabric covering that covers the entire back frame (and leaves access points for straps/buckles or has them sewn on to connect items) or use tape, stealth strips, moleskin, etc....
The other thing I'm wondering is...If you have a bag for your climbing sticks already, maybe something like an FLC would be better for your needs.
Before I started using my turkey vest again for deer hunting (slightly modified), I used to use an FLC (fighting load carrier vest) (also called LBV or Load Bearing Vest)....
It's basically a mesh/fabric vest with PALS all over it. You can pick and choose some dump pouches, grenade pouches, etc, and configure it just about any way you want. That way every item you carry can have a specific place on your vest, and you can put them in areas that don't interfere with shooting a bow, or any other movements.
Without having seen your stick bag.....I'm thinking with that, you could probably feed two webbing straps with fastex buckles on the ends up through a few of the front molle web straps. Attach two of the female buckles to the climbing stick bag you wear now. Now the climbing stick bag would sit on your back and the weight would be carried over your shoulders. When you need your sticks it's just a matter of unclipping the two buckles. This way you could do it as you go up the tree if you have to.
The packs are more for a way to carry a lot of gear and/or meat. The LBV would be just for smaller amounts of gear.
The other thing with the LBV is that you can probably rig it as shoulder straps for your saddle too. I never did that because I go between saddle and stands on occasion and I keep all my hunting gear in one vest. Otherwise I'd have to have duplicate gear, or move stuff from vest to vest all the time.
Here is a LBV though to give you an idea....Without knowing exactly how you plan to use the system, I can't say what is best, or if any of this is good.
https://www.youtube.com/watch?v=AbSmZwamHVA
In any case, I think you'll be happy with the molle frame. You should be able to come up with something very similar to the Tenzing with that. And if you decide to switch to the FLC, they are also cheap and you can always get what you paid for the MOLLE. Lot's of "preppers" and stuff that want this stuff.