TLDR: Basically Zwift with individual training pace partners, roads designed for a given session and the structured planning of trainerroad.
I want something that combines real, interactive riding of zwift with the structure of Trainerroad. You would ride with a bot or bunch of bots (and other humans could join too) and the ride would be designed for what you’re training for. Say you’re VO2 max hill repeats, it’s like going to do them in real life except the route’s perfect - distance to the first hill is idea to warm up, then there’s a serious of hills of the right length and gradient in a nice loop - and you’re training partners perfect - eg you’ll just stay with them if you do the required power, and maybe you’ll beat them on a good day or get dropped on a bad one. Or it might be chain gang, again on an ideal route. Or a group recovery or zone 2 ride where you’ll be off the front if you go to hard. All this would be combined with a long term plan - base, build etc.
A simple version that TR could do would be to have something where you do intervals in nonERG mode and some kind of interactive video where you can see yourself being dropped if you’re under target and pull it back as you increase power.