I really think all the complaints about the CoH2 UI are unfair. If you compare the CoH1 and CoH2 AI CoH2 comes out ahead actually. Inverse why aren't you mentioning the lack of a health bar for tanks that are not selected in CoH1 ? Or the extremely useful unit list in the top right that relic implemented with CoH2 ? I think these aspects are way more significant than the problems that you brought up. I do agree on the tac map issue btw. Never experienced the visibility problem on snow maps so I can't comment on that one.
Because interface issues are subjective. When I play CoH2, I don't see a single interface change that provides more useful information in CoH2 than it did in vCoH. Vehicle health bars being always viewable is irrelevant to me because vehicle health is far less granular than infantry health; it always takes the same number of shots to kill a vehicle using a specific weapon or collection of weapons, so after a while you don't need health bars to know how much HP a vehicle has because you can just count the number of hits it's taken from different damage sources. Would it have been nice to have? Of course! But I never felt like I was being deprived of vital information in vCoH because vehicles didn't have always-visible health bars. Infantry engagements, on the other hand, have a lot more variables in play, and are much closer in terms of outcome. I value quickly accessible HP information a lot more in those fights, and in CoH2 it just isn't easy to see because icons and HP bars are semi-transparent.
As far as my play and priorities are concerned, CoH2's UI is larger, displays less useful information, and is cluttered with more useless information than vCoH's. I don't, for instance, think the unit icons in the top right are an improvement over the unit shields in vCoH. CoH is a small-scale RTS, and the top-right icons in CoH2 take up a lot of space and display more information that I would ever care about because I want to be monitoring and adjusting my units on the field at all times anyways. Furthermore, they aren't easily collapsible and expandable because you have to click the arrows instead of simply hovering over a shield. They also don't clearly separate into control groups (instead the icon just gets a number indicating the control group), making control group usage more difficult.
And this is all ignoring the huge problem of visibility in CoH2, which I intentionally left out because it's been discussed to death and it's obvious that Relic either disagrees or doesn't care. In vCoH, you always knew when two units were fighting because 90% of weapons had very visible tracers. Things like snipers and AT guns left noticeable contrails behind their shots that let a player know at a glance where these units were stationed and where the damage was coming from. CoH2 removed these for the sake of realism, but in doing so made it extremely frustrating to locate the source of any off-screen damage. Add to this the clutter on the tactical map and the previously-mentioned contrast issues on winter maps and you end up with an extremely frustrating gameplay experience.
It's true that Relic has, in general, exposed more information to players in CoH2 than they did in vCoH. I just know that for me personally, the information they added is irrelevant to my gameplay, while the information they obscured is information I want to have instantly and effortlessly accessible so that I can make intelligent decisions in a split second.