Wow! I guess it is really important for people to convey their opinion that hunting the wind is the ONLY important piece of scent control.
However, I'm going to disagree with that notion and hopefully give you some helpful thoughts!
Your intuition about leather IS correct. Leather soaks up oils and grime really well. I think you can go through the same scent control routines as before though, with a few tweaks for leather gear. It's best to start by keeping your leather items free from obnoxious scents, right from the start.
You need to consider the organic nature of leather, and its compatibility with any scent control routines you might go about. I like smoke for cover scent personally, and that isn't going to harm leather. Not sure about scent sprays and such
so test them on scraps in the off season.
As I mentioned, you have to treat anything leather as an odor sponge and handle it appropriately. But I don't think the leather smell itself will alarm deer. It's the smells the leather has accumulated that you have to consider.
I.e. it might be bad to be wearing your hunting boots all around town every day, never washing the sweat out of the liners (baking soda and warm water, btw), and letting the dog slobber on them. But quivers, arm guards, boots and such can be stored in a container with scent wafers or pine boughs, just like camo. You can also walk through cow pies, or mud on the way to the stand, and add better scent associations to the places your feet land.
Oh, about smoke, the bull in my avatar was killed after an hour in a stand of trees with never ending wind changes. Literally every direction was getting my scent stream on a frequent basis, but I'd built a smudge fire to smoke up before hand. NO way to play the wind, so I had to beat it. It works. Cheers!