I'm on a Crux also, its awesome. Its not particularly old school though with hydraulic discs, through axles, 425mm chainstays and a 65mm BB drop. It does have a nice tidy 72.5° HTA though, so it steers nice and quick.
I think the the biggest thing the OP would notice between an old Colnago and a more modern graveller is the hydraulic brakes--I've got some of the cheapest ones made (SRAM Apex) and they're incredible. They completely blow away the mechanical discs I had on my last bike and they nuke the crap out of the Avid Shortys I had on the cross bike before that. Also, more modern gravel bikes put the front wheel farther out front of the rider, which tends to make the bike feel bigger and more confidence inspiring (less likely to go OTB) on rougher/steeper stuff. Some trickery is then applied to the fork offset to keep the steering quickish, but I wouldn't think that it could completely erase the long wheelbase. I don't have much seat time on the super modern stuff though, so I can't speak to whether the trickery is completely effective.