I know it's just a trailer but after watching, I'm feeling a little mehhhh towards this.
Looks like an updated Source engine and not by much. The only thing that really stands out is the textures on the maps, player models look about the same and the guns in my opinion actually look worse than in Source now.
I don't know how I feel about cross platform, I got out of gaming on the PC a while ago, also after 6+ years of CS, I know I'm not going to enjoy playing against PC players because they will definitely have an advantage.
Definitely have to wait and see on this one now unfortunately.