4) An additional "junk" tab where you can move items that you want to sell - alternatively a "keep" tab in your inventory for items that should not show up at the vendor
I use backpacks and pouches to keep the things I don't want to lose on my "market" character while being able to then just sell off everything else quickly. It's close enough to a Junk tab for me, at least.
5) Don't make gear that is store in backpacks disappear from the quickslot after use
This one is particularly annoying. I'd love to be able to store all my rogue's arrows in a pack and hotbar them. As it is, I store most of them just to avoid clutter and only keep the main ones out.
