I often encounter situation when a new user is posting several absolutely non correlated questions as a single quetion. As the result we get a bunch of non-enlightening answers which are very short since they try to cover all the OP's question. Even more one can answer only a part of this questions but do not do this, because he is supposed to completely answer the whole list of OP's question. I suggest to request this feature, and what is more I think it will be useful for all SE sites.
No, I don't think this is useful.
I think a better response to such questions is to leave a comment suggesting that the questions be posted separately, and that the current question be deleted. You can punctuate this with a downvote and/or a vote to close.
It is better for the asker to do the work of splitting the question. If someone else does it, errors could be introduced or necessary context omitted.
I think we should just go ahead and delete all the subsequent unrelated questions in the post, and leave a comment asking the OP to ask them as separate questions. (It would be considerate to add a link to the original version in the edit history, so they can easily copy the contents to new questions.) The result is that (i) we have a single well-defined question which can be answered reasonably, and (ii) the asker is motivated to do the work of splitting the question themselves if they want answers to the other questions. It's a win-win!
This is the last part of Phira's suggestion on how to deal with multiple unrelated questions in a single post.