Tried to catch up on this thread as much as possible so apologize if this has already been mentioned:
The only thing I miss about Sufferfest are mixed interval sessions. As in, I would love for most of my non-endurance interval sessions to be mixed. No reason you can’t work on VO2max type intervals and sweet spot (for example) in the same session. Currently I have to do this by piecing together workouts like Legos.
I asked about it here: Mixed Interval Sessions/Workouts
Not really a thing TR folks get in to I guess, which is a shame because it’s actually a lot like riding a bike, an activity I think most would enjoy 
As others have mentioned I’ve never been too keen on the SF brand of humor/motivation. I’m not 14 years old anymore.