I'm not sure I agree. While the D&D druid has a long history of being a full spell caster, it was mainly the uniqueness of the spell list and abilities that differentiated it. With that gone, I'd like to see what they could do with this new design. I definitely agree with him on the Warlock, they tried to do to much with to small a mechanical space; see all the arguments about the blade'lock. I never really cared for the Beastmaster concept to begin with, but I think his point stands.
The Blade Pact could be fixed
within the framework of Pact Boons, though. It just doesn't stand up next to the other two. If you ignore the one they didn't design as well as they thought (no shade, they did good with the rest of the class, IMO, but at least some small tweaks are needed for the blade pact to work as intended), the Pact Boon feature is an excellent part of the class, and I absolutely do not want to see a Warlock whose boon is chosen by choosing their patron. Each boon makes sense for every patron, and it should stay as it is. Especially since Invocations let you choose how much to focus or ignore your boon as you progress.
As for Beastmasters, as a person who loves the concept, the Beast Master ranger works really, really well now. The PHB version isn't great, but the revised version is excellent.
It doesn't obviate the space for a pet class, but that is a whole other thing, and I don't want a Beast Master class to be the Ranger. if it is a class, it needs to be
it's own class.
Re: Druids: Again, I'm fine with reducing it's casting focus a bit, just not to the point of a half or 1/3 caster, as he suggests. The Land Druid as it exists is not a nature cleric. It is a Druid, and needs to remain something you can do with the Druid class.
And no matter what, there need to be more spells that only Druids and Rangers get (and barbarians, because I'd like a couple more Barbarian options that get spells as rituals, or even as normal spells x/day) that exemplify that tie to nature as a Force in the world, and to the spirits of nature, etc.