You're right on target- Its not all about height but also width. Most of todays bikes are way fat in the seat area adding to perceptions of height and difficulty flat footing.
Like you I've always preferred a good 750-900 class bike, sport touring with decent weather protection, there was of course notihng available when I bought my 08 RT so I've learned to deal with its heft though I'd be just as happy with a punchier, smaller motor that revved better, had a wider torque curve and and 80-90 peak hp. But I'd sure like to keep a good shaft drive. I also intend to look at the 800GT.
My 06 K1200GT feels lower and lighter than 08 R1200RT no matter what specs say..A the late K1200RS (brick motor) lower and lighter yet. The current 6 cyl BMWs hold no appeal for me.
The 800ST was a poor design and miss. Medocre handling, wrong ergos for me.