I can totally relate to that with my first 'Plus' sized iPhone 8 Plus - its fine, size wise, util it goes into my front pockets and I try to sit down - I have to swivel the phone, all the time, to get ot to move in the pocket so its not digging into my leg!!!
I think I'm even more tormented this time around as all new phones seem the same size or bigger. I'd be well up for just upgrading to the slightly smaller iPhone X, if Apple do not discontinue it this September (I don't watch video on my phone so screen size is not that bigger deal. Pocketability is a higher priority for me!)....
I guess I can only truly decide, after the keynote and when I then go into my local branch (Bromley) and actually handle the new devices and physically compare them to my 8 Plus...... No way will I be going down any XS road!