The point is not that they're withholding features because it makes the language too similar to others, and I'm sure that's not what you were really thinking the argument is either. The thing they're trying to focus on is that with ever increasing amount of features, you have an ever increasing amount of complexity added, which has implications on the amount of conversations, decisions, readability and difficulty your team is going to have when tackling any given problem. It can really just be boiled down to increasing features past what is needed can be considered bloat, which does not come free to a developer or team's collective consciousness.
To quote/paraphrase from the 5:10 mark of his talk...
"If a language has too many features, or even more than you might need, you spend time programming thinking about which features to use... you might even spend half an hour messing with a few lines of code to [see how a given feature fits into the solution]... [and even more, when you revisit that code, you have to get back into the thought process you initially went through when determining which features to use]."