Looking at the zwift workout in more detail and yeah there's a real lack of depth when you start clicking through everything. I looked at the 12 week FTP builder and I wonder how legitimate it is when you almost never exceed you current FTP in any of the workouts for even the shorter blocks.
@ratz are the FTP builder sessions from trainer road similar in regard to not many over FTP efforts? Of all the workout folders on zwift the Hunter's challenge seems to have the most variety as well as a good mix of hard efforts.
Well so......
The workouts in Zwift are getting better. What you are seeing is that SweetSpot training is in vogue; it's the best bang for the buck time wise; the theory being that you can get 85-90% of the quality gains from sweet spot and you can do sweet pot workouts 3 - 5 times a week without burning out or getting beat up and injured. Versus only being able to do 2 days of 100% efforts which require more recovery.
Hunter's Challenge is coming from Peaks Coaching Group aka Hunter Allen co founder of TrainingPeaks. They know what they are doing and that's a good all around training plan; albeit it short at 4 weeks. It's a V02Max work focused routine great for when getting final tune ups for event season.
The 2 FTP builder plans are good for those that want to be strong on rides <= 1.5 hours in length; it's target at the Tuesday night Drop Ride people. It's not a very well round plan. It works but it will make you a mouth breather than can't talk on the bike. You really need a solid base before doing that or you get limited results.
The new Winter Plan looks like an proper base plan. That's new this year; and it addresses the need to do something before FTP builder.
The Time Trial stuff is garbage; that's not how you train for TT unless it's like 20 minutes long.
8 wk Race Day Prep is pretty generic doesn't say what type of racing it's focusing on. It's sort of Criterium like but then again it's not.
So in general right now there one reasonable path through the Zwift stuff:
12 Week winter Plan; 10 Week FTP builder plan starting at week 3 and stoping at week 12; then doing hunters challenge. That's 26 weeks total and a good off season plan is going to be 24-28 weeks long.
The problem is they provide zero guidance in there plans so results will depend on what people understand.
A real nice option is TodaysPlan. Which lets you sign up and get customized training plans for your goals; those plans include workouts that you and load into: Zwift, TrainerRoad, GarminConnect, etc; and then ride them on your platform of choice. So without a private coach your options in order is; TrainerRoad, TodaysPlan, and Zwift those are the top 3 in that order for completeness and usability.
Competition is good and all three continue to get better.