Well I'm not talking about overly busy mixes, merely ones with more than a few tracks.
Once the plug-ins are added to multi-track digital recordings is where I hear all sorts of problems. You could blame it on bad code, I suppose, but I think there are some major underlying issues which make addressing these problems rather difficult with the current implementations of the currently popular technology.
In fact, if enough digital tracks are loaded up without any plugs whatsoever, I can still hear problems. I think others hear these problems as well and have complained about it. Simply because they have not translated what they hear into precise scientific terms or math formulas, they have been subject to ridiclue and held up to scorn. I think this is grave mistake. Often the "ear people" and the musicians can hear things before the engineers get around to figuring out that these "ear people" are right about hearing the defects.
In my view, the "ear people" ought to be elevated in the process of moving digital technology forward. Although the descriptor "ear people" is somewhat of a misnomer because you are not limited to the people's ears, but rather, are looking at the extremely complex system that make up entire human beings, and that takes in the the body and the brain, among other things, the "ear people" moniker will have to do until a better descriptor comes along. In any event, this group should not be discounted and should, in fact, be elevated.
Perhaps another way to look at this would be to say, "When the 'ear people' are completely satisfied, then most human beings should be satisfied with the sound of digital. Satisfy the 'ear people,' and the analogue vs. digital debate should subside."