So there are several things in this article that are flat out wrong:

  (1) "No wonder so many languages are derived from it."

Not sure what he is referring to exactly, but Sanskrit itself is a descendent of proto Indo-European, from which many other Western languages were derived. So it is a near cousin to the original language of the Indo-European people, but not the direct ancestor of Western languages (this was a misconception of the 19th century linguists that "discovered" Sanskrit).

  (2) "It is more expressive"
 

I assume by this he means you can do more with less. To a certain extent this is true.

  (3) Very systematic

This is only true to a certain degree. Classical Sanskrit is itself not the original language, and probably the largest single pain point is the "sandhi" rules, in which words are combined together. Although someone eventually wrote down a large number of rules that shows how these changed together, they are more the product of slurring of speech over time, rather than "design" per se.

  (4) "Excellent grammar"

Is a lot of grammar "excellent grammar" ? In Sanskrit, it does allow certain structures that are not available elsewhere (like the existence of a dual case), which presumably facilitate density, and, consequently, presumably also facilitates efficiency. If so, one could argue that the grammar of Attic Greek is more "excellent" than that of English. However, to me "excellence" is something that depends more on the specific use case -- a language that someone can speak and use is better than one that one cannot.