I think his use of the word primary objective is fair. After all its a reaction to the last edition which can had balance as a primary objective at the expense of other large swaths of the enterprise. Not sure if you see this as arguable, but Im sure I could make a pretty big list of things that were absent or signifigantly changed in 4e in exchange for balance.
I wouldn't go quite that far, but no point in quibbling over semantics (which I would need to do to explain why I wouldn't go quite that far).
I will say that a huge chunk of the things on that list that you could make are not absent but substantially present in some other form, or the changes were not meaningful. I'd even bet that I could llst some more pertinent ones that should be on the list that you might miss. Though of course you might surprise me. It depends on how much actual play experience you have with 4E versus hear say or merely reading the rules.
One of the more obvious examples that makes peoples' list is, "I can't play a fighter that is a great archer," or more refined, "at least not until Essentials added the ability 3 years later."
That's a technically true statement as written. But as a complaint about
meaningful mechanics or concept, it is absolute nonsense, cloaking personal preference around a claim of missing functionality. You
can play a straight warrior concept as a great archer, and you could do it from day one using the ranger class.. You even got good melee ability to go with it. If you really wanted to be a "fighter" in the game, absolutely nothing stopped you from calling yourself that.
With something like "early flight", it is a more iffy proposition. It's true that flight gets pushed back in levels specifically in regards to balance, but it is also true that class levels in 4E do not correspond one-to-one with class levels in early versions. Still, it is definitely delayed, just to the extent that it first appears. Whether "having flight now instead of a later" is critical is even iffier. The only real claim it has is tradition, which is important but no more the be all and end all than balance is. Otherwise, you could just as easily say, "I'm upset because my first level wizard can't cast
fireball 3/day," and you'd be on the same ground.
Serious candidates are things like illusion--and even more so, summoning/conjuring. Illusion was slow to arrive in breadth, and limited--not just for balance, however, but because illusion doesn't work very well in the 4E system. This is as much a failure of the "first cut" skill challenge rules as the combat mechanics, though. Summoning/conjuring definitely got extremely nerfed, deliberately for balance. I suppose a better solution there going forward is to let things break the action economy but call them out as such.
For a no-holds barred, real problem along this line, look at all the silly little restrictions and loss of flavor on magic items, in the initial rules. Some of these got gradually relaxed over time. But you know the worst thing about this? It might have been done for balance reasons, but it really didn't add to the balance much, and relaxing it seriously wouldn't have hurt balance much. Plus, it was overly fiddly for whatever balance results it did supply. Initial multi-classing has some of the same problems. This is classic case of things that were done ultra conservatively initially because no one in charge really knew how robust the system was.