This is actually my speciality (been training people in general and business English for 20 years or so, both native English and non-natives, as well as translating/interpreting). I speak English, Spanish, Catalan and a little Japanese, I can also communicate more basically in any Latin language and to some extent in German.
So here's my take...
When it comes to grammar, I think English is actually a quite simple language (*). You have a relatively small number of grammatical forms, compared to e.g. German or Latin.
(*) I would be ROFL if it turns out this sentence is grammatically incorrect :lol:. I'm not a native English speaker, so I don't know for sure.
I want to add that one of the main problems with English is the terribly inconsistent connection between spelling and pronunciation.
First up, your English is flawless, never known you to make the slightest mistake. I wish more native-speakers your age were so good. Your points are absolutely spot-on.
English grammar is basic (the base verb grammar can be written on one sheet of A4, the other aspects on another), and the exceptions pretty marginal.
The spelling-phonetic system is completely out of whack, never having been adjusted in 300 years, and reflecting pronunciation around 400 years old. There is NO linguistic authority in English and several people (like Mark Tawin and GB Shaw) have tried to make spelling more rational, but nobody listened to them.
The vocabulary of English is awesome. The nuances in physical action and expression verbs are incredibly detailed.
... you don't have grammatical cases or genders, you only have two grammatical numbers (singular and plural), a very simplified tense system and dumber-down pronunciation. For me, the most complex part of learning English was the latin alphabet. And attempting not to choke on the "r"s.
Also true, but the question of pronunciation depends on where you come from. Spanish has 5 vowel phonemes, Catalan and French (I think) have 10, but English has 16 (or more if you count some dialects). The difference in pronunciation between "peel" and "pill", for example, is completely inacessible to most Spanish speakers.
Don't worry about the "r"s, there are at least three different types. Say them how you like.
For example the US say Center like that but we (meaning AUS) say it like Centre (along with the UK also).
That's "spell" diffferently not "say" differently. Actually we say it more or less the same (except that Americans don't pronounce the "t" in this position and say "Cenner"). The spelling is different convention, in this case introduced by the US lexicologist Noah Webster in 1834. He wanted to go a lot father in reforming US spelling, but only changed a few things (-re endings to -er and -our endings to -or, and stuff like that).
Sorry for such a long post but this is both my profession and my passion. Believe me, I could go on like this for pages.