Calm down @ZexaronS! Its for reasons like this UIs stagnate and end up staying bad. Im not saying your opinion isnt as valid as anyone elses here but youre going well over the top over something thats purely conceptual and not even an official venture.
Just to reiterate on that, this is a community based effort which means it comes from people who use the engine and quite often not just someone who joined the forum to complain.
Now onto some objective points!
#1. minimalist UIs (including simpler icons) are easier to maintain, if you look at 3dsmax it has literally hundreds of icons. If you look at UE4s UI it is actually quite flat, its not fancy 3d graphics even though it has that ability and then some being a GPU driven UI.
#2. you dont actually have to be a fan of the style to find it functional as with any tool. I might not like the look of a claw head hammer but it entirely doesnt matter to its function. Which leads me to…
#3. it doesnt matter who makes the hammer, it doesnt have some hidden corporate agenda to force its ways on you.
#4. just because someone likes something doesnt mean they are bending to the wills of popular culture and cant think for themselves.
I actually believe game developers to be some of the most open minded, free willed critical thinkers there are!~
Now no one said anything about mandatory adoption but since you brought it up then yes, if the world is to move in a forward direction we cant always bend to the will of the lone old guard soldier holding rank. We have to consider these changes with a level head and in an objective way which is beneficial for not just a vocal minority.
This is a topic on UIs so can we please get back to it and leave the politics to something like compilers or license agreements lol!
Oops I hadnt seen someone already replied, but yes lets not 