upstart doesn't provide sysvinit. It's entirely correct that ubuntu-minimal gets removed, because when you install upstart, you do not have a canon minimal ubuntu installation.
The right solution is to change the dependency in ubuntu-minimal from "sysvinit" to "upstart", which is planned. ** Changed in: upstart (Ubuntu) Status: Unconfirmed => Rejected -- needs Provides: sysvinit https://launchpad.net/bugs/58731 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs