You made many great points Alex. Here are some comments:
… if you upload your own ride you can repeat it indoors.
This statement helps me understand your point of view much better.
My use cases for structured training don’t include simulating outdoor rides. Let me try to explain. In Erg mode, I enter target watts either by FTP percentage or directly in watts because that is the amount of work I want to do based on my training plan. The numbers are entered as line items in the workout sheet. There is no simulation software used here. We ask the bike to give us X erg watts and that’s what we get. If we want to compare riders, we apply watts/kg to the results.
When I do a resistance workout I still want to specify power targets. I would prefer to specify watts at 80 rpm. This gives me a predictable X watts @ 80 rpm, 1.2X watts @ 100 rpm and 0.8X watts @ 60 rpm. It is also easy to apply %FTP conversions. We record the results to measure the amount of work performed in watts/second, and all is good. We apply watts/kg to compare riders like usual. This is a good description of how the NordicTrack implements their resistance mode. You will also notice, everything centers around Watts. That’s what we ask for and that’s what we measure.
Slope mode is different. It’s a simulation function. The actual number of watts / second is determined by the bike vendor’s software. Specifying Slope is OK for resistance workouts. It is just not very predictable. Slope is weight based so we cannot use watts/kg to compare riders. This seems odd to me. Instead we will measure the watts / second that the bike produces, for each rider. We will never actually know what that number will be ahead of time because each bike vendor will produce different results for each rider, based its simulation software and hardware.
Summary: While I can get Slope to work with structured training, I would rather ask for a certain amount resistance (watts @ 80 rpm) based on my training plan and then get just it.
@Alex: You described the calculations you will need to import GPX/TCX files. I can see why slope is important here. If you want to simulate a real word ride, then you need slope to make the simulation feel right. I have always consider that to be a Zwift use case because it is a simulation game. I didn’t know this is a structured workout use case. Is replaying GPX/TCX files really something you want TrainerDay to do?