The 874 flex pair that I tried on seemed tighter all over than the usual 874 pants, but that was one pair on one day and I didn't buy them, mainly because I had so many of the normal 874 pants, but I didn't want to have options for different things and then buy a whole lot more.
In general, from buying half a dozen pairs of the same pants at the same time (yes even same colour) when I had a good deal, the fit and sizing varied significantly, so as much as some will be just right, others were way too big and some were too small, so I don't know if anything has changed in that regard, but trying them on is a must, or more commonly buying a size up and just going with whatever comes, as I have learned to do over the years.
I like the bit more room the next size up gives me as well, but everyone wears them to their own tastes. When people were wearing them lower, they were more likely to rip the inseam or have other issues with limited movement as they are designed to sit high, compared to the other 873 or 872 versions, which sit a lot lower on the hips than anything else.