It's going to be very difficult to determine a set of standards, seeing as we're dealing with so many broad genres and particular tastes. I also feel like I don't want to see this place getting to the point where we're saying "Your question was closed because you didn't word it correctly... even though everyone knew what you meant" just for formalities sake.
My personal take on the above listed 7.
- "Self Imposed Restrictions" - This could be summarized down further, but it's too broad and mildly off-topic that I feel it should remain closed. If the question was, instead, something along the lines of "In the game X, what are some ways of alternating your play style to make the game feel different?", with a healthy explanation in the body text, it might be able to pass.
- "What games offer a good co-op multiplayer experience?" - Too general. The list could go on forever, and "good" is completely subjective. My passion for MMORPGs and FPS games may be completely lost on the OP.
- "Easter Eggs in MegaMan games NES (1-6)" - It's not directly beneficial, but easter eggs are definitely a part of the gaming experience for some, if not most. Still, this particular question draws on a large collection of games, and as mentioned, we could be seeing this for every game which would just create unwanted noise.
- "PC voice chat software" - Even though it's not about a video game or gaming related, it's a very closely related topic that I personally feel is warranted on the site. If we're going to allow questions like thisthis, I feel that asking about preferred software to assist in gaming is perfectly within the scope of the site.
- "What are the popular openings/builds for Terran in StarCraft2" - This seems a tad localized in time for my tastes. Especially for RTS games, strategy is constantly evolving around the metagame. Unless that particular answer gets updated by the person every time new strategies come out, it's not going to be relevant 100% of the time. A better question might ask for links to pre-existing strategies, such as on a heavily updated wiki.
- "Healer add-ons for end-game raiding in WoW" - Again, localized, though less so than prior due to the general evolution of add-ons / mods. I think as long as people are careful to craft their questions/answers in these types of questions, it'll be fine.
- "GTA-4 like games for PS3" - I think this is fine, as we're defining the genre, the platform, and asking for similar style games. I can't bring much opinion into this, because no matter how much I say "Street Fighter is like GTA-4", nobody will believe me. I can voice my opinion on games that are listed, but that's beside the point.