it is basically Stock Android with a few touches here & there it is good enough as it is
Whilst this is true, even Google make efforts to add new features to each revision, and OEMs build on top of that with their UX. OnePlus is another such OEM, with their own tweaks and bits thrown in which is perfectly fine, but nothing seems to have changed since the last generation of OP phones in this area. It doesn't feel like you're getting anything extra for the extra money being spent. This is mostly a smaller nitpick I guess, as anyone who is familiar with Android will be immediately customising with third party launchers and apps anyway and making it better than stock.
Why do you need HDR on a phone?
Nobody "needs" it, but for the money, and it being a flagship, it's kind of expected/desirable. It also means the screen is brighter in stronger lighting due to the requirement for the HDR specification. Netflix, Amazon and others are now starting to support HDR for mobile devices as well, and if you've watched any HDR content on a mobile display next to a phone without HDR, you'll know how much of an improvement it is, especially on a nice big AMOLED panel.
Maybe the reviewer prefers a smaller screen, with no curves & funky aspect ratio
This could be true, but he had an S8 as a "daily driver", which leads me to believe he was perfectly fine with it.
The 1080p panel will be better for battery
Plenty of comparisons on phones that have resolutions options show it makes marginal difference going from 1080P to 1440P in terms of battery life. There is a difference, but it's too small to worry about. Visually images and videos look similar, but text does ever so slightly appear sharper at higher resolutions.
but are there any out there that are?
LG G6, also a QHD+ display, also HDR, also very sleek and professional looking. The new iPhone will also be an edge to edge display, and lots of Asian market flagships now have them too. 2017 seems to be the year fat bezels get the chop.
solid upgrade but nothing special.
Pretty much sums it up. It's not £500 special vs the 3T. And considering the S8 can be bought for similar money now... You get the idea.