Can you point what "nonsense" is he peddling?
I will chime in.
1. Bass traps don't fix bass modes. As Dr. Toole says in one of his private presentations, "the only thing bass traps do is trap your money!" Wavelengths are way too large for any traditional velocity absorbers to do much good. Often people put a ton of them in there to get results and with it, make their room too dead. In general, few if any people are in a position to use velocity absorbers to make effective changes in their room. Pressure absorbers work better but they are expensive and require skill to design and use (they are very frequency selective).
2. He is optimizing for his eyes, not ears. Two ears and a brain don't work like a single microphone and a graph as Dr. Toole would again say.
The notion that reflections are "bad" is folklore as comprehensive peer reviewed has repeatedly shown. Yet, it has become one of the "internet rules" to chase them using measurements. Doing so will lead to a completely dead room when you are done. Ask any high-end acoustician what the #1 problem with DIY acoustic is and they tell you people creating dead rooms because of this mistake.
2A. Use speakers with proper directivity and you will not need to fear reflections. Indeed, this is your #1 tool for good sound in a room.
3. Rooms are never ideal. The calculators for room modes and such for the most part generate incorrect results because your walls are not perfect reflectors. Ditto then for golden ratios, and this and that dimensions not being good. Read Dr. Toole's book for example measurements showing this. For this reason, you can actually fill nulls a bit because cancellation unlike what he claims are way away from ideal (or they would not be down just a few dB).
4. Reflectors need to be broadband. Those skyline diffusers are not. And neither are a lot of what you folks slap on walls. Minimum depth should be 4 inches.
5. DSP is extremely powerful. Get the right speakers, put them more or less where you like, and set your seating position the same. Then measure and apply DSP to pull down peaks. This is the formula which will give you 90% of the results with minimum expense and uglification factor (slapping panels everywhere in the room).
Sadly the folklore has gotten so bad that if you don't have a room full of acoustic panels, folks think something wrong with your room.
What is really wrong is that people haven't spend $35 on Dr. Toole's book and a few days of reading and learning about real sound acoustics. Please, please do not follow the Internet consensus on this. They are just wrong.