Given you vast experience with vintage equipment, don't you have some favorites with regard to intuitive design and layout of controls?
There's layout and usability along with almost the ability to operate good ones in the dark. So not myriad of tiny black switches you can't see or a whole lot of knobs that all look the same in a row etc.
Just thinking of integrated amplifiers, here's just a few that popped into my head. Many of these I have in my collection or have had:
I like the classic Yamaha CA-xxx series, the CA-610 as an example below. Nice positive paddle switches, solid grub screwed volume and selectors made of aluminium.
(all internet pics)
The symmetric Marantz models of early Standard Radio Corp design like the 1060 right through to the late 1970s 1152/1180DC:
Sony had a range about 1976/7 which was lovely, very easy to operate with excellent and positive controls- all built like mini battleships.
TA-5650 Vfet
In the 1980s, good design pretty much went out the window, along with fashion! And angles, flat controls and lots of plastic became the norm. Lots of flat panels, 'touch' controls and very few actual knobs to grab hold of. More time was spent peering at the tiny writing and lining up your fingers to push buttons than listening to music! It was not a great period IMO, be it Japanese or US made stuff. Think SAE and SUMO, ML etc. It was all black and flat with random angles, touch up/down buttons and rows of red LEDs.
Late 80s things got a lot better and into the early 90s there was some lovely design, again from Yamaha, Sony, Pioneer, Rotel, Marantz, Denon, and much of the product of course was now black finish. Harder to see controls and markings, but easier on the eye in many ways.
Yamaha AX-xxx series about 1990/91. Yamaha finally softened the edges, and added satin finish and rounded knobs- gone are all the sharp angles and putrid design of the mid 80s.
Sony's 1987/8 TAF-xxx series. Sony was finally softening HiFi with scalloped solid knobs and only kept just enough of the hard edges to allow last year's models and this years models to mostly match up.
Rotel's early 90s RA/B-xxx ranges are stylish still to this day. The controls are simple, but sometimes IMO a bit small on my fingers.
Think of the classic Pioneer A300/A400 from 1991/2. Just a lovely amp to use with no frills:
By the time silver came around again in the late 90s early 2000s, most of the major manufacturers had given up on proper 2 channel HiFi. One of the exceptions was Sony who still had a small range of decent 2 channel gear, some in gold, some in silver/black.
The FA-xES range (a few models) was very nice and a delight to operate:
And then we have sources, tuners, decks, processors, preamps, power amps, CD players etc.