There isn't really a rule however I want to link the discussion in the front and it would be hard to if it's interspersed with multiple posts of other characters. A couple is fine but when about 40% aren't about the character is when I start to not like it. Also I would like to keep random Matchup discussion in the other thread while this thread is more focused. I don't need high level level play against every character or videos for every matchup as most characters aren't in high level play but that doesn't mean we should treat them any less. If there is less discussion on one character than another then that is fine but I would like for a character to run it's course before switching to a new charcter to keep it organized. I can't, nor want to, write a detailed summary of every character that incorporates what everyone who discussed on it said. The biggest example I can think of is Mario. There is a great analysis of Mario by @BSP but I didn't put most of it in the summary because it's too big.I don't see any real reason to make rules blocking discussion on past characters, especially considering it's going to be significantly harder finding high level tournament gameplay of Marth v Pacman. We only really need to update the index if something insane is discovered (like Greninja being able to 100% shadow sneak out of Boost Kick and ZSS f-smash, or 1.1.shieldstun).
IMO one of the major issues other boards have had is that they burn out and go nowhere/decide they want to revisit a character after x discussion and never do. IMO we should just set a current main topic character every x time period and try to get some general combat tips for every character, back-editting in important stuff that's brought up for old characters.
But in general my plan was basically what your second paragraph was. I just didn't tell anyone. I would also like to get the thread back on track.