Appreciate you considering it.
To clear up any misunderstanding, I’m specifically asking for Current Speed & Total Distance displayed during a workout on the app.
Training by Speed in place of power or HR is another subject, which I also added as a feature request.
There is no reason having Speed/Distance as options would need to have any effect on anybody else’s preferred training methods. Ideally it would be optional.
Ultimately, having customizable data fields/displays is the only way you’ll appeal to and suit the needs of a wide variety of individuals.
I am already using my Garmin head unit at the same time, and it displays current speed and distance. I sync my TrainerDay workout with Strava, and it provides speed and distance. Neither of these addresses being able to see my current speed and total distance during a workout in TrainerDay.
This is just my personal opinion and preference, and I can’t speak to what is important to everybody else. But I like having current speed displayed as I translate everything I do on the bike back to being on the road or trail.
Truly hoping TrainerDay goes the direction of appealing to a wider variety and greater group of users, from casual users to racers. A rigid training app will always only appeal to rigid group of hardcore users. There are plenty of those out there. A flexible app can appeal to the millions of people who do not, and will never, invest hundreds/thousands in gadgets and just want to hop on the bike and ride. Appealing to that wider audience could make the lower price model of TD a success. And with a few simple settings/options for customizing how we want to train, could be clean and effective and still appeal to the most hardcore.
Again, just my $0.02 
I can think of at least four people right now who have basic resistance trainers who I would recommend the app to if they could just hop on with a speed sensor and ride. They would be the type of people to pay $3-5/mo and happily work out a few times per week while watching TV. They will never buy power meters, track training stress, don’t care a whole lot about data, aren’t racing, and won’t spend $20/mo on software. But there are lots of them out there.
Seeing how fast you’re going when you’re on a bike is one of the most basic metrics in cycling that has been around forever. Speed matters! 