Let's edit imperfectly posed questions which are salvageable.
What I have learned from my participation at Academia SE and ELU SE is that when a newcomer asks a question that isn't on topic, rather than just slapping "closed" on it, it is best to edit the question to make it fit the site. If it is too broad, the constructive editor should prune the question, keeping the most on-topic portions and removing the hopeless portions. (Of course, if no portions of the question are on topic, then the question does indeed need to be closed.)
Example: Questions about a few grammar and vocabulary points
Portions of this question were acceptable. They might not have been acceptable according to the stringent requirements of English Language & Usage (ELU), but they would have worked at English Language Learners (ELL). Our site doesn't have the luxury yet of splitting into two sites about the Spanish language. Let's try to avoid appearing unfriendly and unwelcoming to newcomers.
Let's take the time to teach newcomers which questions should not be answered.
Example: https://spanish.stackexchange.com/a/26521/9385 (deleted answer to the above question)
Here we have a new participant who clearly needs some guidance. Yes, we should teach newcomers not to write answers to badly posed questions. But it takes time to learn this. As we are training participants in this, we should keep in mind that although this may be obvious to an experienced site participant, it is not obvious to a new participant. In fact, this is not even always obvious to a medium-experienced participant.
The guidance comment given to the author was
Please, if you are aware that a question is off topic, do not answer it. Instead, use comments to help a bit and mainly persuade to improve the question.
Everything is great in this comment except "if you are aware that a question is off topic." We can't assume that a participant of reputation 141 understands this. Granted the author's sentence "P.S: Tell me when have you read this so I can delete it" does look suspicious, but it would be a rare newcomer who would truly understand (a) what is on topic and what is not; and (b) why it is not a good idea to write an answer to a badly posed question. I've even seen experienced participants need a few iterations to understand (b). (And I remember that I didn't understand this myself at ELU until my rep was in the four figures.)
To avoid rebuffing newcomers who want to help Spanish learners, we can be more careful about our assumptions in our guidance comments; and a moderator can convert a portion of the newcomer's answer to a comment. It can feel like a slap in the face to have a long answer summarily deleted in its entirety.
Update
It seems my salvage effort is still too broad to pass muster. Would appreciate guidance now to edit further, or additional editing from those with more experience. Of the remaining parts, which I left intact because I thought they showed effort, I'm wondering which is/are more/most work keeping? I would like to end up with something that can be answered. It seems a shame, when someone throws a big handful of questions at us, to throw them all out and not answer any of them.
I would like to end up with something that can be answered
One of the problems in that question is that it has several unrelated questions, even if they are answerable. As it's now, Q1 is answerable (although a proper question should give some context + some examples of intended use). For Q2, if we don't have something addressing that already, same thing: in a separate question I would provide some more context when asking "when I used this over that?". For Q3, very broad, and we have a wealth of questions about "ser vs. estar". Q4 and Q5 are just trying to get corrections in a text.