I would call these more "caveats" than "problems" -- anything with a title like "weirdest languages" is going to be incredibly subjective, and there will be no doubt no shortage of people who disagree with specific choices, but as long as the reasoning is clear it can still be interesting/useful.

> This could explain the result for Hindi - it is a standard language that 'averages' a large number of other Indian languages.

I think this is a little misleading; a lot of Indian languages come from a completely different language family to Hindi (Hindi is Indo-European, but a lot of Indian languages are Dravidian, e.g. Tamil and Urdu), though I'm not qualified to speak about this.