They literally ruined one of the most memorable moments of the series because they wanted to create a hashtag so that people get roped into the next season opener to find out #WhoIsIt
You are being played, when a show starts making concessions in it's writing and story because they want to rope people in for the NEXT season, it's time to admit that whoever is in charge doesn't actually care about the quality of the show.
Think about it, they don't actually trust their own writing or characters to simply carry the fan base to the next season. Instead of us knowing #WhoIsIt and then thinking about all the consequences of that death that will drive the next season forward as well as ENDING THE FUCKING SCENE, they chose that the story isn't strong enough to carry people over to the next season and thus literally cut in half the final scene into two seasons.
Cliffhangers usually have some form of conclusion with the cliffhanger leading into the next arc due to whatever just happened at the end of the episode/season. Good cliffhangers are S4a, S4b. Prison arc is done, everyone is scattered and we get a conclusion to the Governor character. S4b starts with everyone scattered and heading to Terminus and ends with the majority of the group united and stuck in Terminus. Clear defined story arcs that have an end goal and reach them while putting the characters in a situation to launch them on their next season arc.
A good cliffhanger doesn't literally cut a scene in two for the sake of "WHO DONE IT!?". You're not completing an arc, you're not giving characters motivation for what comes next, you're just ending a scene before it actually ends.
