IMO, no, it isn’t horrible to have the unused tasks. AFAIK, to maximize the usefulness of the functionality, you really don’t have any other choice.
FWIW, I dug up an old workflow that might help you by way of an example. In this workflow, both tasks REQ2.06 and REQ2.13 are next milestones for REQ2.01, and both have REQ2.18 as their next milestone, thereby bringing the branched logic back together, but only temporarily. Tasks REQ2.22, REQ2.23 and REQ2.24 all are next milestones for REQ2.18, but each of those branches leads to a separate milestone (REQ2.25, REQ2.26 and REQ2.24, respectively) for completion of the workflow. HTH!
