ELL is for people who are new to English, so how can we place emphasis on keeping all answers simple? What would be the guide lines? As an example
My 2c.
ELL is for learners, yes, but that doesn't exactly mean non-experts. It means those who did not learn English as a mother tongue. Some of these are actually very fluent in English by this point, and quite good at helping other non-native speakers with some of the mindset changes necessary to learn English. Others are moderately fluent, but are still missing some important bits of the language. Either way, the crucial point is not so much the lack of skill in the language as the different mindset — that's why the site exists as a separate entity, not merely "ELU, kiddie pool section".
In general, I simply edit to fix any mistakes I see that are quite unlikely to be a stylistic choice, including SHOUTING, "bad" use of punctuation, evil word choice, and overuse/misuse of back ticks. (I see a lot of mistakes.)
Answers should be as long as necessary, but no longer; as correct in their use of English as possible, and as free from error in what they recommend as can be. Answering language shouldn't be dumbed down too much, but does need to pay extra attention to clarity and avoiding ambiguity or fancy tricks except where absolutely necessary to demonstrate a point concisely. An answer that does not explain should be downvoted, edited, or deleted; an answer that cannot be understood by learners in practice should be downvoted or edited.
Meta isn't just for learners, it's also for the teachers. There is a lot of material on meta that would be difficult for a beginner to read, but its purpose is not just to explain things to learners. It also helps define what the community standards are for the site.
If the folks fluent in English aren't clear on what is a good title on ELL, or what the qualities of a good question are, or when a question should not be closed as "proofreading", then the way the teachers interact with learners is going to be confused and chaotic as each person acts according to their own ideas.
Also, answers should fit the question. If the question is asked simply, the answer should be stated as simply as possible while still being useful to more than just the person that asked it. Simple is not the same thing as short though.
I have some worries that when someone fluent in English corrects the grammar of a question to make it correct, even though it was understandable with the mistakes, that folks that read the question after the edit assume that the asker is more fluent than they actually are, and that leads to answers that might be too difficult. We do want questions and answers to be useful to more than just the person who asked the question, but I think they should help the asker first and everyone else second.
