Spanish's Dreaded Four Horsemen

Below are the four parts of the Spanish language that non-native speakers struggle with the most. Compared to these vocabulary, aural and written comprehension, reflexive verbs, commands, masculine vs. feminine, and even rolling the 'r' are easy to master. Why can't Spanish be cool like English?

1. Por vs. Para (very basically, for vs. for)
2. Preterite vs. Imperfect (the two past tenses)
3. The Subjunctive (too difficult to explain fully: basically it deals with expressing doubt)
4. Ser vs. Estar (the verbs to be vs. to be)

I guess if these four parts of Spanish were easy, the language wouldn't be as much fun. Besides, if it were easy then everyone would be speaking it (less the continent and a half as well as a European country, among other parts of the world).