Okay wow you just deconstructed most of my arguments. I've studies two years worth of German so I'm familiar with it; yeah, it has its own god-awful things (for me it was always plurals and whether a noun was die/der/das. Our teacher gave us a list of what he called "fairly encompassing" endings for masculine/feminine nouns, e.g. a noun ending in -e with more than one syllable is usually feminine).
To counter/discuss/etc some points you made:
1. When you mention the six endings for German verbs, that is admittedly another thing to memorize but it's fairly trivial; within less than a week, most people can tell you what person/number a present tense verb is. Compare to Latin, where every verb (save deoponent, semideponent/defective, and most impersonal verbs) has over 120 ways to conjugate it, and there are four different verb classes ("conjugations") that have slightly different rules, primarily for the perfect tense stem. Parallels exist in the modern-day Romance languages and most eastern European languages. Adjectives have 30+ forms depending on what kind of adjective it is. German(and Germanic languages' in general) verbs are comparatively simple. Additioally, your point about verbs being nouns in German applies in English as well- "I love to run" uses the infinitive as a noun; "I love running" uses the gerund as a noun. However, I do have to cede that in German you must learn gender, based either on the large list of what masculine/feminine/neuter nouns
usually end in or more likely just as a vocabulary entry, and their genitive forms. One-up on English for difficulty.
2. Correction on tenses- five past tenses. Simple ("closed"), with "have" ("have closed"), with was (verb)ing ("was closing"), with did ("did close"), and with had ("had closed"; I grant it's the past tense of "have" but it is a different case none the less). Four if you count have/had verbed as one. And as pointed out above, the German present tense is not terrible complicated, though I grant it is more complicated than English's "add -s if it's he/she/it."
3. Point ceded. But yeah, the progressive tense only exists that I know of (almost certainly in places I don't know of as well, though) in Icelandic, where you would say literally "I am to read" ("ég er að lesa"). And I guess my point here was fairly invalid to begin with, because A) other languages have plenty of their own tenses (referencing Latin again, there's six (perfect/imperfect/pluperfect/present/future/future perfect), plus a passive for all of those and a subjunctive + subjunctive passive for four), and B) other isolating/minimally inflected languages form most of their tenses with auxiliary verbs, like English.
4. Yes, other languages do have spelling quirks, but (again, just in my experience) most other languages tend to be fairly uniform and there are some exceptions. English seems to have far more exceptions to its rules than most other languages- the G is zh in "genre", hard G in "god", and like a J in "judge". English spelling seems more out of whack than other languages to me.
5. Your point on vocabulary- I would imagine it doesn't make a whole lot of difference in terms of learning the language if you have to learn one word and its different meanings based on context versus learning a different word entirely; you still have to store about the same amount of data. Though I must say that German compound nouns can be nicer than some of English's words (off the top of my head, only ambulance = Krankwagen ("sick car") comes to mind, not the best example). But those compounds can get nasty.
Ultimately, I would say that English is probably not all that hard to learn, or at least not moreso than any other language- I guess I kind of misrepresented that in my post, or more than kind of- but it has some (occasionally very noteworthy) snags. Though if, as you seemed to imply, you're a native German speaker, it might not be so hard as if you spoke, say, Russian or Finnish; the largest differences in English and German are mostly vocabulary, plus grammatical gender; the grammar aspects are fairly similar for being different languages, down to some of the idioms being almost verbatim (e.g., I believe "schlafen gehen" means the same as "to go to sleep" in English, which would be its literal translation. Not 100% sure on that, though, it's been three years since I studied any German

). But some of the false friends are dicks (Gift = poison, for example. I can see some awkward situations with that one) English and Latin, though, or English and, say, Yoruba, are totally different worlds grammatically, vocabulary-wise, and semantically.
But then if we're going purely from a grammar standpoint, English shouldn't be that difficult to learn. The grammar is fairly straightforwards, it's jut learning the spoken version (as with literally every language on earth) versus the written/proper version that's more difficult. But then again, same goes for Chinese (almost a purely isolating language; almost no inflection at all).
Also I know I've probably got a few glaring inaccuracies/flat out wrong things in here, but it's 11:00 at night here and I'm tired as all hell. And as mentioned I studied two years of German three years ago (been studying Latin since), so I've an admittedly limited understanding.
EDIT:
Xero Scythe said:
Anah said:
.. wut?
It's not. It's pretty much the easiest out there.
No, it's actually the hardest for non-natives. English has so many dipthongs, silent letters, slang terms, and exceptions to the rules it is incredibly difficult for anyone to learn it after childhood.
Every language has dipthongs (oe, ao, ai, etc in Latin; ch, au, äu, ei, ie, etc in German; au, ey/ei, hv, fn, etc in Icelandic, and so on), and every language has extensive slang. That's not a particularly English-specific thing unless you're trying to speak to someone speaking in Cockney Rhyming Slang, in which case, I believe you are legally allowed to hit them with an English textbook. Also, it's incredibly difficult for anyone to learn any language after childhood; there's a certain window where you can acquire it without any difficulty (up to some age I don't know off the top of my head) and from there to around 14 is where you can acquire other languages with relative ease but still with difficulty; past that it becomes very, very difficult (increasingly so as you get older) no matter what the language.