The ending felt incomplete, but the entire final season did due to dropping the religious aspect of the story that was in the book and comics. The introduction of The Lumen seemed to be going in that direction, but I feel they cut the series short and didn't get to do what they originally wanted. Would have been cool seeing The Master vaporized in the final blast, but the budget for the season may have been cut short, bridge destruction scene used a lot of that up.
I enjoyed the series though. It may not have lived up to its' promise (much like The Walking Dead), but it was entertaining.