But I'm really with Linus when it comes to the leading, single asterisk. It looks totally weird, IMHO
/* A small, concise comment that doesn't fit a single line */
is easier for the eye than
/* A small, concise comment
- that doesn't fit a single line */
where your eyes somehow stick on the asterisk first and then have to search for the real start of the line.
FWIW I don't care about the difference between the two, I'd be happy to switch to the former form if we decide that's what we want to do. I only care about having full extra lines in there.
We've currently already merged --ignore=BLOCK_COMMENT_STYLE, so all of these forms get accepted by Gerrit right now. I don't think a tool that automatically reformats comments would work that well (that would probably end up causing other unintended side effects), and I don't think we should set a hard line limit to decide between comments either. (For example, in a header file where you're describing the API for every function prototype you'd probably want all of those to use the same style, even if some of them are longer and some shorter than the hardcoded limit.)
I think we should decide on the two styles of comments we want to allow, and then we can either submit a patch to checkpatch (I'd hope they'd accept it if it adds a configurable switch, such as --comment-styles=blank_line_top_bottom,short_balanced_stars) or enforce it through a separate script in util/lint/. And update the Wiki page, of course.