Always allow a logged-in user to edit his/her own posts.
Short, concise description of the idea
At the moment, it is not always possible for a person to edit his/her own posts (see "Full description" for examples, if you need). I think it should always be possible.
Full description of the idea
If you are not a member of the suggestions Community, then you can post to it using the suggestion generator, but you can't edit your posts afterward in any way. I think you should be able to. Similarly, I think, with a Community that you have posted in but since left (which might be useful if you want to edit/update your post in response to Comments).
An ordered list of benefits
People would be able to fix malformed suggestions, etc. (see andrewheadley's two most recent posts in the suggestions Community for an example; he made small, easy-to-make errors that he would gladly fix if he could).
People would be able to update their suggestions and Community posts to reflect new Comments, etc. (for a suggestions-related example, if I can't think of any drawbacks but three people post with some, then I could add them to the post itself to maintain the logical order of the post).
An ordered list of problems/issues involved
I can't imagine that intentional misuse of this could be a concern, but I suppose it usually is; if anyone has any thoughts, Comment!
Unintentional misuse could very definitely be a concern in the case of suggestions among people who are unfamiliar with the HTML for unordered lists and such (e.g., they might not understand that they need to use <li> tags to enclose list items); resultant problems could go anywhere from confusing-looking posts to, I suppose, malformed HTML that makes the entire page hard to view. This could be dealt with, I suppose, with a suggestions re-generator, but I'm not sure whether it's worth it to do that (I'm not sure how much work it would be). Maybe only allow people to delete, but not fully edit, such a post? That's more limiting, but would still allow people to fix major problems by regenerating their suggestion later.
That's all I can think of at the moment; if anyone has any thoughts, Comment!
An organized list, or a few short paragraphs detailing suggestions for implementation
I imagine that when you click on the pencil in a Read/Post Comments page to edit a post, there's some kind of code to make sure that you have posting rights in the journal or Community that contains the post; I think this code can be simply removed, but without having viewed the code, all I can say is that it would require editing. (The reason I think the code can simply be removed is that the pencil only appears in the toolbar, as far as I can tell, when a logged-in user is at the Read/Post Comments page of a post that he himself/she herself has posted, in which case he/she should, in my opinion, always be able to edit the post.)