Just to pick holes, it's not the lack of torque that's the problem; you just need more power. It's the lack of efficiency that's the issue.Wheel size is only 1 factor, but if you look at the market now it seems that most bike are 29er now? Except for ebikes on hub.
I used the bbs02 750W for a while on a road bike it felt rolling better than normal ebike.
Unfortunafely, chain and cog require too much maintenance for my taste and I'm decided on DD.
But for example, a bigger wheel would also absorb better road asperities and be more comfy... and somehow rolling better? I'm tempted for a 29er on a DD but fear the lack of torque
In all honesty though, do you have any 'real world' problems with 26" wheels?