a bit of context: I am using a no-gear bike (Bodytone DS60), which is like riding a fixie into Watopia. If I want to simulate gearing, I play with the trainer difficulty control. This proves to be a bit tricky while doing an effort, as you have to select Menu/Settings and then adjust the scroll bar… not easy.
For those of us in such situation, which I believe will be a increasing portion of your customer base, I would suggest setting up simple key shortcuts. That would be an effective way to “adjust gears” amd that would greatly improve the user experience of us fixie-riders.
Hope this makes sense.