I actually think it is more important to find an issue that will get people to actually engage in mailing action.
I think it is fine if the issue doesn't include everyone, because the next issue could be your issue. This is more about actually trying to engage in action, instead of just discussing things here.
I think it is a crying shame that we have this internet thing, that makes it really easy to find people who agree with you, and yet it never seems to be used for joint political action. Well it does, but on Facebook and Twitter, where the FBI starts giving you special attention.