Yup, I agree that it depends on what you'll be doing and which parts of Europe you'll be exploring. I'm assuming you will be going there fairly soon, during the Northern Hemisphere winter.
Leather to me is a "cold" material---maybe swap it for another woolly jumper?
Just make sure there's still room for air to circulate between each layer and, of course, between the innermost layer and your skin.
Go for layers that you can easily take off (when going into heated buildings and vehicles) and put on again, e.g. ones with zippers, snaps, or even Velcro rather than ones you need to pull over your head.
Keep your head, ears, neck, and lower back covered, too. You can skip the gloves if your jacket has good handwarmer pockets. And wear warm shoes, or two pairs of warm socks!
Now, if you're planning on an Arctic trip, it's probably best to get a synthetic down parka. I did fine sloshing around the snow in Norway last winter with just three layers---a parka, a cotton T-shirt for some colour/variety, and a Helly Hansen baselayer. I didn't have proper winter boots so I just wore two pairs of socks and psychedelic gumboots.
Oh dear, I've gone into way much detail yet again. Hope that helps though!
Eats shoots and leaves