if you very seldom carry your iPhone 7 now, due tot he LTE watch, the I'd skip the X.
With the AW3 LTE I can leave my big 7+ in my car and still make calls while I'm out hiking or biking in case of emergency. So phone size isn't an issue anymore.
But I like how my 7+ works in landscape more like a nano-iPad, while the X runs in landscape like any other iPhone. So I'm considering canceling my X order now, regardless of having the AW3 LTE or not. For sure my 7+ is still plenty responsive with iOS 11.0.3 so speed isn't a reason to get the X.
When I have my 7+ I like to use it like a tiny iPad in full landscape mode (rotating icons on home screen, tabs in browser, dual column support in apps like notes, mail, settings, calendar, etc). It's small enough to take most places, but occasionally I may want to not carry it around.
So far I have kept an old iPhone 6 as a spare for those instances when my 7+ was too big, and now I have the AW3 LTE so I don't need to downsize with the X. The X will be only so I don't have FOMO (fear of missing out).