TL;DR: Do not answer in a comment. Do not change the question being asked, unless it is your question. You are free to post the 'alternate question' as a separate question, providing it follows the rules of the Arqade.
First and foremost, you should not post an answer in the comments. This is bad form. I can give a couple of reasons behind this:
1 - The comment section is often overlooked when scrolling through. By having answers in answers and clarification in comments, we make it easier to identify the possible solutions.
2 - If your comment answers the question, there is a good chance OP won't put the effort in to reword their question. In this case, the OP is a new user, who last logged in on the same day that the question was posted. I try not to assume that new users are just going to 'dine and ditch' - we all start as new users, at some point - but in cases like this, the odds are not in our favour.
3 - If your answer adds merit, it would be easy to "hijack" your answer. You obviously have an amount of experience in context of the question - but if another user was to post the same information as an answer, your answer could then be removed for low quality, as it adds no additional content to what has already been posted.
Secondly, if you change the question entirely, you change the intent of the question. This is something OP would have to do. In essence, you interpret the question to ask for a list of spells that work in a given situation. That list is quite extensive, so instead, you support changing the question to ask for a list of spells that do not work in the same situation.
While it seems pretty obvious that you could derive a list of working spells from a list of non-working spells, we can not assume that that would still address the exact same problem. It probably will - but ultimately, that is OPs call to make, not ours.
Solution: Post your interpretation as a separate question, and answer it, yourself. Comment on the original question with 'related question [my question]'.