I'll wait for the Slim version too. Whenever I get interested in the PS5 I remember how much I don't like the size and looks of it. More power to you if you do, but it's not for me. The controller seems cool though. I'd expect the slim ps5 to be digital only, but if I can backup my games on a hdd, though it doesn't seem possible right now, or similar I don't care for having a blu-ray disc of it.
As it stands now next week the most interesting console in my opinion is the Series S, because of its price point and the fact that it's not aiming for 4K which won't be relevant for me anyways since my TV only does 1080p 120hz and not 4k 120hz (which I doubt will be targetted much this gen anyways..). Storage size doesn't matter much either since you can just plug in an external usb ssd or similar and get decent speeds for your previous gen games, which to me is interesting.
I'm in a bit of a doubt about how you'll actually be able to buy older games to get them on your digital only system though, be it xbox or playstation.