I agree with Indigo's stance here:
I think these types of questions need to state a criterion firstly. E.g. who is the best Water Pokemon for HGSS? Who is the best special attacker among the pseudo legendaries?
I think these types of questions are fine and can be answered objectively if there's been a good effort to narrow down the options and give specific measures for comparison. Where we draw the line with that is pretty much left to staff discretion, it's difficult to make a hard and fast rule that works fairly for everything in this instance. Basically, the options should be restricted (e.g. "which is a better Water-type special attacker?" not "what is the best attacker?") and should have reasonable means of comparison (e.g. typing, stats, abilities etc.) If the question doesn't do that, then flag it. The less open the question is, the better.
How restricted must the options be? Again there is no hard and fast rule and it'll be assessed on a case by case basis. A question could ask for the most reliable damaging Fire move -- of which there are dozens -- and you could narrow it down to two or three options pretty quickly since you're not comparing much besides power and accuracy. So I don't think it helps much putting a number to it; but if it means anything, that question about the best pseudo legendary is probably on the furthest border of what I'd allow personally. There aren't too many Pokemon there, but there are many more factors to consider in that question which might make it hard to prove one particular Pokemon as any better than the rest.
I personally think none of these questions should be allowed unless it specifies whether it's for playthroughs or competitive battles, and which version for playthroughs and which format for competitive battles.
Fair enough, it's very helpful when the asker specifies this and you should definitely request it from them. But if they do not, you can still provide an answer for each situation if that's reasonable. You could first justify your answer, then detail which cases your answer might be different given the scenario, if any. So if one option is much better than the other in HG/SS but worse in others, your answer could be "[x] Pokemon, except in HG/SS for [x] reasons". A similar principle could apply for the format -- it's very helpful but not entirely necessary in my opinion.
If the answer isn't to the asker's liking due to their lack of detail here, then that's more or less their problem. You can edit your answer if they do let you know it's not exactly what they wanted, or somebody could post another answer covering it.
