Yeah, a lot is that. But then some really basic things crop up. i.e. the scroll bars and zoom tools aren’t of a ‘normal’ look and so always seem a bit cumbersome when i mouse towards them. I’ve moved from Mac+Logic whereby the trackpad could be used for two finger scrolls and zooms into the timeline, but now on a Win10 machine with a Trackball i’m having to navigate and use UI elements such as these, and they’re very small, windows doesn’t have that same OS level scroll to it, plus i’m without trackpad now!!
The difference between UI elements doesn’t concern me too much, but the expanding and collapsing of groups down the side to get to controls i want seems to command more clicking than -always- just having the Inserts in view, for example.
Also, Steinberg seem to want me to use their quick EQ controls, whereas i’d prefer to get the full EQ on my screen. So again, that’s extra clicks.
Then there’s issues whereby the low/high EQ cuts needed colour changing on my system to be more evident visually.
And other elements such as when using Groove Agent SE and you want to perform manual slicing, there’s no tool icon, and there’s no button for slicing… Instead you’re supposed to ‘know’ that you have to hold alt+click (Or is it shift? i forget lol) and select part of the waveform. That’s a big sin, and makes you wonder what else you’re missing out on when discovering such shortcuts that really should have a tool.
And one other thing, i always get lost looking for Quantising note lengths (Which i rarely use), it’s not in the MIDI menu but somewhere else and always trips me up, i wish it was down in the piano roll editor.
I think the interface depends on user environment. Are you laptop, single or multiple video monitors, what size and how many?
I run on twin 1080p screens on a tower PC, have a 2012 Mac Pro on the same display and 1080p 120hz MSI laptop. So i do feel jealous when i see Cubase on a Higher Def display, are you saying it’s a better experience on hidpi? 
Does Steinberg know better than you? While every user is unique, I would guess they group users into categories, conduct relatively extensive data research compared to competition
Honestly, I just presume it’s due to the German influenced design philosophies, whereby things are very functional with ‘prettiness’ being a secondary concern. I’m hugely productive with Cubase, by a considerable margin vs other DAWs.
As above, it’s not a design i’m fond of, so leaves me scratching my head how it yields me great results. I think Cubase encourages you to be very deliberate in how you approach tasks, and that maybe has a knock-on affect on my music in a zen like fashion? lol. I really don’t know. haha.