Of course number of keywords is not everything. But it usually correlates well with number of syntax rules, which correlates in turn with usages per keyword. To get a more accurate picture one also needs to look at the size of the whole context-free grammar. I did not do that for F#, but for many other languages, and found that, again, Scala is at the lower end of the spectrum, smaller than Java, Kotlin and (I would guess) F#, a lot smaller than C++ and C#, about on par with OCaml, larger than Python.
But of course, number of syntax rules isn’t everything either. Maybe we should stop identifying “small” and “simple”, There is probably a correlation between the two, but it does not look very strong.
Also, if I look at @haoyi’s argument, it turns out that plus points of languages sometimes correlate with extra features. Scala improves on F# because it has higher-kinded types, whereas F# is better with computation expressions. Both of these are examples where a language spends syntax footprint in order to make something simpler which would otherwise have to be encoded (sometimes akwardly). So, that’s another argument why perceived simplicity and size do not seem to be strongly correlated. It’s a bit sad for me, since I was operating under the assumption that the language ideal is to be small, orthogonal and very expressive, so that features can be provided by libraries. It seems the world does not agree that this approach leads to simplicity, overall.
Which is not to say that Scala has not made mistakes. Like any other language it has warts and dark corners. We are trying to fix some of these in Scala 3, and that will hopefully be an ongoing effort.