The thing about lowering a bike and reaching the ground sort of has two different aspects for any given rider. Stretching a bit to reach the ground is fine 98% of the time; under normal and predictable circumstances.
The problem is when something goes wrong and that stretch can't be easily or safely accessed in an instant.
So the width of the FJR is what gives me the most trouble at 5-9, 30". I have a lot of lifetime miles and have managed a lot of different bikes without disaster, including GL15 and GL18s, and that even includes with a passenger larger than I.
Last summer, coming to a stop at a rural stopsign, looking for traffic, I missed seeing a small pothole where my right foot was going to land (I'm old school and go right-foot down. From my BSA days, I suppose.), attempted to plant and found an inch and a half of pavement missing. By the time I could react, the bike was on its way to being on its side.
Maybe twenty years ago I could have saved it by brute strength, but not anymore that my rough-tough carpenter days are a distant memory.
Would a 3/4" lowering have prevented the tipover? I don't know for sure but I suspect so.
So it's not necessarily the normal, more ideal circumstances that are at issue with seat height- it's the out-of-the-ordinary ones that have the potential to make trouble.
2004 V-Strom 650
2020 Ninja 400 in the hands of the Missus
2004 Suzuki SV650S, also Hers
2008 BMW F800ST, mixed.
In the avatar: 1966 Velocette Venom Thruxton and 1967 BSA Royal Star.