Even if the question was "how many 2* champions are there?", saying "every answer is equally valid" is just wrong.

"What’s your favorite ______?" is 100% subjective. Where "How many X exist?" is 100% objective. The answer is a number, doesn't get more objective than that.

"What happens if there are multiple posts with different sources, all with the same data? Or similar data, but with different features? Which answer would be correct?" The one with the right number...

"Also, SE frowns on link only or short answers, so if the question can be answered correctly with a link to a wiki page, it is not a good fit for the community." As far as I know, they will indeed implement this feature in the game... so the link answer would be a palliative solution, therefore valid, IMO

"A better question would be..." that's what I ended up asking, after Frank's explanation...

@GabrielOshiro Please read the directions on comments. Yes, my original post lost most of its meaning when I did the quick edit at the end (rule quote was wrong and removed key pieces). I have updated it to be more clear. I wanted to fit in the fact that your question does not show any research, but I did not have the time to fit it in. FYI: Frank's suggested question is also not a good fit (which was what the multiple posts paragraph was referring to). Neither was mine (I will fix it) because the answer is a link.

"Lists which will quickly be out of date (and unusable by anyone else)." Just to be clear. The answer is not a list. I am not asking anyone to list them all. I am asking how many X are there? the answer is a number.

"One line links." The problem surrounding link-only answers comes from the fact that people post the link and eventually the link will become broken. Than the answer is not valid anymore. What is encouraged by SE is to provide a stand alone answer and provide the link as additional source. So, if one day the link breaks, the answer still holds up. Which in my case, it is just a number. So if the person answer with a number + link as reference I would say it is 100% acceptable by SE standards.

"A better question would be 'Where on the Marvel Contest of the Champions web site can I find the number of 2* champions?'" Maybe a better question, but that's not what I want to ask. I don't want to know specifically on a website, I want to know if that information is provided anywhere in the universe, including in the game itself.

Is the answer going to be a fact? YES, it is a number. A number that might change over time. But given a certain point in time, there will always be only one correct answer. That's why I asked here on meta first. To understand the policy concerning questions whose answers vary over time.

"Is the answer going to be useful to other people?" The answer here is YES. But even if the answer was "NO, it is only useful to me", are you going to tell me that every single question asked on stackoverflow are useful to other people?

"Is the question already answered (on the site or on a site I can search for on Google)?" this is just a bad idea... I read many many many discussions about "googleble questions" on meta. And most of the time, people agree that it depends on the question. I give you an example that I can remember concerning Apple forums. You can find very similar questions asked on AskDifferent and apple forums. Go ahead, check both and tell me which one is the easiest to find answers. The fact that a question was answered before doesn't mean it is not welcome on SE.

@GabrielOshiro This is too chatty, if you wish to continue, please start a chat and add it as a comment. FYI: there are multiple problems with one line answers and link only answers. FYI: the list of criteria I added was in general, not specific to you question. Also, you question with the answer of 21 will result in knowledgeable users listing the 2* champions to get around the one line rule.

I don't know how to do that :P that's why I use the comments. But anyways, I said pretty much everything I had to say. Unfortunately I don't think you're making valid points on your answer.

@GabrielOshiro Please review the comments rules, as this is too chatty. Not knowing how to do something within the rules is not a reason to break them. My point is that your question is off topic for the site. If you feel you can justify it better, then we can meet in chat.

I'm not sure how else to say this: you are wrong. We have our own rules, they are not superseded by anything you quote, and we don't appreciate someone with so little investment in the site telling us how to run things.