Hey, if a cameo styled carricature offends you, let people know. It might not get the poster to actually change it, but it can affect such things as the GM hinting that such actions aren't appropriate via alteration of success rates.
And herein is where I think we hit the biggest issue. The starting point. I've considered dates as early as 1988, giving plenty of time to go and fuck with the Fourth Grail War before it could even begin. However, assuming that one was 18 at that point, by the time the mid-2000s roll around, along with main characters, you all'd be in your mid thirties. Which could make interacting with the cast kind of awkward. I'm also assuming you'd all like to stay relatively young during the more active parts of the game.Well, we'd likely argue a lot over what to do. Most of us who actually care about the characters probably have goals which are not mutually exclusive, though....
And, whilst some people would indeed "goof off", a lot wouldn't. There are a huge bunch of characters in the Nasuverse who need help of some kind, and most of us care enough about at least one of them to go out of our way to fix their issues.
And hey, nothing stops an argument like having to deal with a bunch of the Dead showing up to eat your face. So, there's other things for you guys to worry about.
EDIT
And I am, quite horribly, ninja'd.
Also, are you guys really that passionate that you'd beat each other up over pairings? I know the Internet can be SERIOUS BUSINESS but geeze.