Hacks are totally appropriate for game rec. TRPGs are a heavily DIY-based culture. From a pure "System Does Matter" perspective, it's often better to recommend a way to reskin and tweak a system that's a good fit for the goals of a game than to recommend an appropriate pre-built setting with a ho-hum system attached.
If someone doesn't want to hack, they can specify that in their question or just ignore your answer.
As I suggested in this meta answerthis meta answer, the key to suggesting hacks is to actually teach us what to do in your answer. Now, your answer should be actionable, but I don't think it needs to do everything. But you have to "teach your reader to fish" by sharing the fruits of your play experience and system mastery — clearly signpost the hardest and most important changes, and make at least a passing mention of the other kinds of things to be aware of.
An answer should be more than mere speculation. A good answer should have a clear and detailed understanding of the issues involved in making a hack like this. Because there are issues that come up that aren't obvious from an armchair viewpoint. "Oh, I dunno, hack my favorite game, I'm sure it'll work out fine" isn't a useful answer.
Direct experience with a similar situation is ideal. (I don't think it needs to be identical; that'd be an insane and counterproductive requirement that excludes too many good answers to be worthwhile, I think.) Indirect experience, i.e. you've read a bunch about someone else doing it, can also be useful — you should definitely link back to the source so readers know where they can go to learn more, though.
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