I have multiple approaches to ascending and descending, which directly effects the pack I use. However, each setup contains my 'necessities'...flashlight, headlamp, platform attachment, tags, knife, kill kit, RF, chemical handwarmer packs, etc. Since I am not typically hunting miles from my vehicle, after shooting a deer I wait and assess my next steps. Sometimes that is backing out and returning and other times it is getting right on the blood trail. Once I've made recovery, then tagged and field dressed the deer, I take my bow and saddle gear back to the vehicle to lessen bulk and bring back the lightweight sled that lives there all season, for getting it out of the woods solo. That is my basic mode of operation...
If hunting private, I often have either preset sticks or paracord to quickly setup my mainline to ascend via JRB footloop.. Once at height, I reach back and take my platform from the rear saddle clip and secure it to the tree. In those instances, my CGM Vice Carrier works really well, is compact and pretty lightweight. I added a pair of quick release nylon straos for attaching a jacket or vest to the outside, plus having my coiled mainline easily in reach. One of the aspects of a bigger pack is the profile off the side of the tree or leaving it at the bottom, so you don't have immediate access to the contents. If I am on bigger public tracts, I sometimes use my MR Treehouse 20 pack to bring in four Tethrd One Sticks and a platform on the outside. Other times I forego a pack and hunt presets from my LWCG Ambush that has quick release buckle shoulder straps and a small pouch with necessities.
Finally, the saddle itself. Some like a 'no frills' saddle and seriously dislike side pouches. I've tried that, but then everything that would go into a pouch or two is now in your pockets or in your pack...which is often more difficult to access. I have a Cruzr horizontal dual zipper pouch on my left hip that always contains the linemans, a William carabiner for rappelling and a couple handwarmers. If using preset sticks, I bring a short tether in the main pouch along with the linemans and a mainline, I bring a JRB DIY Garda footloop. On my right hip I have a smaller collapeable molle pouch that holds my bow holder strap and fittings, folding saw inside and bow reel, spare mini-flashlight, S-biner and spare carabiner on the molle outside. In the view of some, I am far from minimalist...but I only bring what I know I am going to use on a successful hunt. I don't haul in food or water on short duration hunts of a few hours, because that isn't why I'm there.