I am not "concern trolling," and I believe you need to not say that to everyone that has different priorities to you. As I noted I mentioned why I think UX and UI are important.
In addition, first I've got the DE preordered, so your implied take that as a "concern troll" I'm shilling for Xbox is bullshit. I don't have the XSX preordered but likely will purchase once the launch hype dies down. Two, one of the reasons I chose PS4 over XBOX as my primary system (I ended up picking an XBX later down the road) was the complexity of the initial UI screen on MS's console, in addition to the fact it had advertisements on it (much to my chagrin Sony has been doing this as well lately). What MS chose to emphasize - a messy Home Screen and advertisements on a premium product gave me a sense of their priorities. Third I both am a UX designer and a design instructor. I can understand the take that maybe UX/UI is not important to you. But I go to my class three times a week explaining to students how critical UX/UI design is, how it's a conversation between creators and users, a statement about the product itself, and the life blood of the users interaction and experience with it. If you are unable to grok that, it's not "concern trolling," it's your lack of perspective.
PS4's UI has changed over the years. Not for the best all the time, particularly if you have a lot of games. They've added PSN sales. They have emphasized social networking. There was a 6 month period where I would get spam via PS4 messaging which would alert on my PS4 and my phone through the app. The app itself is a pretty amazing piece of crap. As I suggested above the UI and UX will also help inform us how Sony sees the market, what it wants to push, and how it will balance its needs vs. user needs. How will my huge library of PS4 games show up? Will they be regular titles or will BC be tucked away somewhere? As a consumer electronics company Sony has crafted some absolutely terrible UI. The UX of the confirm button change is a big deal in Japan just by itself (if you want my bonafides, I have one US phat PS1/one JP slim PS1, one US/two JP PS2s, one US/one JP PS3 slim, one US PSP Go, one US/one JP PSTV, one Japanese original Vita, in addition to US PS4; this button change is a big deal for me too). How will that work with PS4 games? How will my downloaded PS4 games on an ssd and their save files come over (if they do - I've shelved my copy of Yakuza 7 because its save file won't). I've been playing a lot of FF14 lately - am I going to be able to get into the game more quickly or more slowly? Will the web version of the PS Store work on safari again? Will the console version be easier to navigate and faster? So I think your rationalization that it can't be a disaster is also bullshit. I think it's unlikely but it's not outside there realm of possibility - to use some other Sony products or even the PSN store. Maybe it's not a disaster but I am interested in these questions because they impact my day to day with the machine.