I rarely use the erg mode, 99% of my rides i use the resistance mode.
I think that the sliding bar to set the trainer resistance is not the best option.
Sometimes i need to adjust just 1%, but doing that while at threshold or Vo2 is almost impossible.
Maybe a +- or arrow up/down buttons are better for more accuracy.
Its just a suggestion to make the experience better
Thanks a lot
Looks like more and more users are moving away from ERG mode workouts. Anyways, why not try some other apps, if you’re not tied to TR.
If you’re using the PC app its like that. (Left & right arrows) and you can quickly toggle ERG off with ‘t’, which I do too 
Im using the iPhone app
I thought you might, either that or Android, ipad or tablet, which is probably the majority of users. TR need to extend the PC usability to them.