It's definitely an issue if we're unnecessarily closing questions. From looking at your examples and several other more recently closed questions, I think we're being a little more aggressive than I'd like, but not insanely so: we could try to close questions slightly less often. However, this is a very small number of questions: we don't close that many in the first place, and most closures are boring and obvious. So no matter what, I don't think we should think of it as a severe site culture problem.
I would try to avoid making this about Magic, though. It's possible that there's some interaction there due to the difficulty of asking good subjective questions about Magic, but it's just as possible that we're being overly aggressive about closing those questions - not all non-factual Magic questions are impossible to write good answers to either. And bottom line, it's always going to be hard to tell whether the issue is Magic or not: StackExchange users in general are pretty skeptical of potentially broad or subjective questions, and the Magic community here is large, so the two are going to overlap whether or not there's a causal connection.
I think this issue is best addressed by examples. You've provided two, and I'm happy to try to address others too.
Risk strategies. For now, I'm a little skeptical - it doesn't seem very narrowed down, the existing answer seems to show that it might be a bit of a rabbit hole, with a lot of small pieces required to provide a real answer. But I suspect there are other examples of strategy questions that might not be so potentially problematic. This particular one might also be salvageable, but I have no idea - I don't really play Risk so I don't know how to narrow it down.
Learning a complex new game. I think is one that we should try to improve and reopen. It's a totally reasonable, practical question that a lot of people will face: a game is difficult and time-consuming to learn, so how do I address this, get over that initial hump, and actually end up playing? There are definitely multiple approaches, and probably some approaches will work better for some people than others, but it seems like exactly the kind of experience-based good subjective question we should try to help people with. If https://rpg.stackexchange.com/ can exist, surely we can manage something like this.
In general, with the aim of closing a few less questions (ones that right now are more borderline), what should we do? A few things I try to keep in mind when looking at questions:
Hard questions are not always bad. Yes, it's hard to say what the best strategy is for a game or situation, but you can still say some pretty useful things. To look at it another way, even if you don't know the answer and think you'd have to write a book to figure it out, someone else may be able to do a decent job in an answer.
Answers do not have to address every detail. It may be true that if you take the question literally and attempt to answer it exhaustively, you could write a book about it. That doesn't make it impossible to write a useful high-level answer. And again, even if you don't know how to find those important high-level points, someone else may be able to.
The possibility of subjectivity is not inherently bad. It's very easy to say "it'll be impossible to prove answers, so it's all just opinion." That's not a constructive way of looking at things. The issue is whether answers will be completely dominated by opinions, or whether there's room for some reasoned arguments and experiences to back things up.
We don't always have to do something right away. It's easy to find yourself searching for something to do on the site, and trying to always close questions before anything bad happens. But it's also okay to let things go for a bit; we can always close a question later if it gets plenty of bad answers and no good answers.
Read the whole question. Don't get caught up in specific phrasing, or in the title. Read the whole body. One bit of phrasing might sound subjective, but the question overall might be fine. If there is some non-ideal phrasing, this leads us to...
Questions can be improved. Often when asking a question, the OP doesn't realize how broad or subjective it is, but others with more knowledge of the subject will be able to help refine it to attract more useful answers - possibly just by editing. Obviously we can't always have time to fix everything, but it's helpful for your first thought to be "can we fix this?" rather than "do we have to close this?"
I think we should keep those points in mind when looking at new questions before voting to close, and also when looking back at old questions. Let's let some slightly subjective, slightly broad questions (perhaps about strategy) get answered. In many cases, we'll probably find that nothing bad happens, and the site will be better for having those questions.
Of course, I should also be clear: many strategic questions really are too broad or subjective. If there's nothing in the question to help narrow it down, just a wide-open "how should I play this game?" it probably won't work well. But not all questions are like that.