The quick shifters on the 2019 GS I had and now on my 2020 GSA are “agricultural” compared to the one on my Ducati.
They work better going up the gears for sure at around 4,500 - 5,500.
I do agree. The LC boxer engine will probably never become an excellent candidate for smooth operation with quick shift, and I think the reason is as follows:
Gearing up, QS technology is based on cutting the ignition for a few milliseconds, allowing the engine rpm to drop during the time shifting from one gear and allowing the higher gear to engage. The catch is, the engine has a flywheel, heavier than most comparable bikes, and this flywheel + the internal mass of the engine will try ro keep the rpm up in a stronger way than an engine with lesser/none flywheel. Hence the jerking action when shifting.
As the rpm rises, the internal resistance of the pumping action (both pistions move in and out simultaneously)will increase, helping to dropp the rpm, thus it feels like the QS works best at higher RPM's.
Downshifting, the same issue applies. The 'blip' of the engine, increasing the rpm to meet the required rpm works best at lower RPM. And if the RPM does not quite match, the inertial weight of the engine components will be felt stronger than for most bikes.
Compared to other BMW bikes, as well as most other brands, the Boxer stands out, both with it's heavy flywheel, it's ability with strong pulling power at low RPMs, and a jerky QS. Drop/lighten the flywheel, and the QS will improve. And the low RPM pulling power will be reduced.
Sorry mats, we can't have it all.
As a personal notice, realizing the short comings of the QS, operating it when knowing it's short comings, is still acceptable. But I seldom use the QS when riding the bike two up.