* It'll be needed for at least one other distro, but I don't know what the correct package names are and I don't plan to test it, so I'll let someone upstream worry about that.
* It's not doing the pacemaker bit, it's just ensuring that corosync starts with the correct plugins loaded.
* Because there is an architectural separation between corosync and pacemaker, and not everyone who wants corosync will use pacemaker.  Two other reasons: a) it keeps pacemaker to a manageable size, and b) Tim agreed with this approach.