There is no doubt that all of our potential battleline options are pretty bad, especially the knights.
Compare Horrors to any other medium sized infantry, like Bullgors. Bullgors are considered a mediocre unit and they are better in almost every way, they are cheaper, do more damage, do mortal wounds, have a better save and a better heal.
People are excited for Flayers thinking they are going to be this amazing alpha strike unit with deadwatch and blisterskin. There damage output is still really poor, they are completely reliant on Feeding Frenzy to do any work. That doesnt meld well with them flying off away from your army since you need to be completely within 12" of a hero to get the buff off. They are also so squishy that they are unlikely to survive the retaliation from your opponent to get to use the Deadwatch ability. This is easily the most overrated unit in the book and I feel people are going to be incredibly dissapointed when they get them on the table. They are best at hovering around the edges of the battlefield playing cleanup and picking off isolated units, they are not a hammer.
Even ghouls are aweful if you compare them to similarly classed units. They are inferior in every way to Plague Monks and are vastly more expensive.
All of our non-hero units are 30-40pts overcosted. This puts us in a situation where we are incentivized to max out on our overly efficient characters and minimize our other units. I actually think the podcast gives more credit to some units than they deserve. Anyways, they are very correct in that we have very limited competitive options. Either you go monster mash or you focus on abusing Archregents. Anything focused on knights cant get enough wounds or damage output on the table to be effective.