I'm impressed that you can cook in an 8-9" deep vestibule. My 1.3L pot is 6" diameter, so that would leave about an inch on either side between the pot and the tent fabric, except that my windscreen is a little wider still - a bit dicey.
I disagree with your statement that the X-Mid "doesn't seem much better" with regards to fitting a dog in the vestibules. The X-Mid has perhaps the most generous vestibules of any lightweight solo tent at 29 sq ft (vs 17 sq ft for the HR1 or a token 5 sq ft for the Big Agnes Fly Creek UL1). You could easily fit a large dog on either side. A dog on one side and regular hiking stuff on the other would be a nice setup. Whereas you wouldn't fit much of a pooch in the High Route vestibules.
With regards to doors and slope, Like the HR, the X-Mid fly also has a decent overhang above the inner so you can keep the doors open in light rain. Further, since there is some slope to the door walls, if you only open the X-Mid doors about half way and roll them up like that, you get a lot more overhang (much more than the HR) so you can keep the doors half open even in moderate rains and still cook, enjoy views etc in conditions where you'd want to have closed the HR doors. I don't think you'll find the X-Mid lacking compared to the HR in this area, but both tents should be fantastic partners in the rain compared to mainstream tents which often set up inner first and don't fully cover the inner when the door is open. Both the X-Mid and HR have large functional vents, large doors and fly's that overhang the inner, so this seems a bit like splitting hairs between two good tents. But the X-Mid does add no-sag polyester fabric, which makes a substantial difference in wet conditions because the pitch stays taut.
With regards to water on your back during entry/exit, I think the biggest factor here is how high the door is because it's really hard to duck under a low door and all doors are going to wind up wet eventually. Some mainstream tents have really low doors. For example, the MSR Carbon Reflex 1 is impressively light but mostly because it is tiny. The peak height of the inner is only 34" (versus 43" for the X-Mid and HR) so you can barely sit up even at the highest point. Naturally, the doors are lower still, so you'd be hard pressed to squirm out in wet conditions without touching the fly. Comparatively, both the HR and X-Mid have quite large/tall doors, so they should both be relatively easy to enter/exit while avoiding touching wet fabric. If the exterior of the X-Mid door (or any door) is really wet, then I roll it up with the roll outwards (rather than inwards) so the water is trapped inside the roll and drips out the end further away from the inner.
Regarding one handed operation of the inner nest zipper, this is difficult to do in any tent because there will commonly be angles where you pull on the zipper and the inner isn't secured in the opposite direction. In general, it is easy to pull the zipper down away from the inner peak with one hand since it has that solid connection at the peak, but if you do the opposite (pull it up towards the inner peak) you may end up just pulling up the floor fabric rather than closing the zipper since the zipper has more resistance. The X-Mid inner zippers are above average in this area because I've spent a fair bit of time trying to get the inner as taut as possible (whereas many tents have a limp inner that makes the zippers harder to use). So most of the time you can operate them with one hand. You should be able to pull the zipper slider down from the peak, around the corner and all the way to the other end with just one hand. If you do the opposite (pull the slider from the bottom end to the peak) you'll probably find that it briefly needs a second hand to get around the corner. The only way around this would be to secure the inner to the ground here either by staking it down or connecting it to the bottom of the trekking pole. I could have done either, but I think occasionally using a second hand is better than adding weight, complexity and more steps to the pitch.
Overall, I think the largest advantages compared to the HR are the much lower weight (28 vs 37oz), larger vestibules, no sag fabric, no vertical fly walls and simpler/no guyline pitch. I'm leery of guylines that extend far from the tents body because myself or someone else often finds a way to trip on these which can damage the shelter. I also think the X-Mid is more wind worthy, but I can see how this could be a red herring since the HR is likely good enough for conditions a backpacker will encounter. More broadly, I think too much discussion on shelters focuses on unlikely hypotheticals rather than practical real world differences. Differences in weight, space and ease of use are real world differences that meaningfully affect a backpacking experience, whereas theoretical differences in wind or snow shedding almost never matter in the field. Certainly you don't want an inadequate tent, but I wouldn't choose one tent over another because it might require less banging to get the snow off on the rare occasions where it snows.