Current favorite is the Stylophone DS-2. Amazing sound and functionality in a small footprint!
But historically I’d say Roland SH-09, Analogue Solutions Telemark, Korg MS-20 (v1 filter) and Erica Syntrx 1 and 2 (not really “WYSIWYG” however.) I wouldn’t put modern Moogs on the list as so many functions are only accessible via software editors.
My stage goto synth (think: rock bands) is the Little Phatty.
Its WYSIWYGness is debatable as it does have some menus, presets, and does not display all settings at once. However those LED collar knobs almost give me the feeling of having a full panel.
Other than that -call me fanboy- the good ol’ MiniMoog is one of those simple yet charming instruments.
Had the chance to play a Voyager Old School and a Vermona '14: two pure WYSIWYG boards but they both are just about to be too complex for that simplicity feeling.
Norand Mono MKI => v.1.99 firmware stable. Just an amazing sounding synth. Shame about the flakiness of the company.
SH-101 => don’t own one but I’ve had the SH01A twice. Just love the sound. Simple and straightforward. I also love the sequencer and triggering it externally with gate patterns.
My knee jerk response is that the Syntrx is that synth. But then I recall that back when I did a lot more writing than I do now, I strongly preferred LaTeX - a language that embeds markup commands in text, vaguely similar to HTML (but superior in every possible way) - to WYSIWYG word processors like Word.
That leads me to question whether any synth is truly WYSIWYG. The Hydrasynth has a 'scope mode, but that shows what you get after you’ve turned knobs and pressed keys,
Is there anything other than a sample board that shows waveforms on its buttons that is truly WYSIWYG?
A Yamaha CS30L for me (the one without the sequencer).
Picked it up in the early 80’s and had it for many years. Got to know it inside out, a great learning tool.
I have often thought about picking one up again.
I had 15/15D at the same time and I was surprised that with a similar design and even more advanced functions with CS15 they had a completely different sound…the sound of the CS15 was completely ordinary and I immediately exchanged it for moog LP.