I think the big thing is what does cables through the headset gain you? The answer is nothing of value and only more headache. There are a fair amount of negatives and the only positive is it is "cleaner". Except all those cables still loop out to your levers and shifters and remotes anyway. Now the just coalesce at the stem instead of 4" lower in the frame.
Perhaps. I just really don't see it as that much extra headache for me. It was a marginally longer process to take things apart. And I do that basically never (possibly because my use case is hot/dry Arizona where maintenance just isn't needed on items in that area).
What negatives have you identified with your headset routing?
I value the marginally cleaner cockpit I suppose. And as cockpit controls start to be designed with this in mind (see the new SRAM brakes where the brake line exits the lever basically on the bar) tucking cables out of the was will be even easier. Couple that with AXS shifting and droppers and soon wireless lockouts, and a single brake cable is all there will be to think about.
For what it's worth, when I disassembled everything, I removed the brake lines from the levers and shortened them. I didn't even need to do a full rebleed of the brakes. Simply do the simple shimano lever/cup dirty bleed and everything was perfect.
I guess I'm curious as to what everyone is doing with their bikes that they need to be changing out that upper bearing so frequently. Because that upper bearing is really the only thing that is even marginally more difficult to change out than routing cables through the sides of the frame.