For the record, I have yet to hate any seasons of the Flash so far. That said...
I voted "It was ok 50/50" but let me be clear here. Make no mistake, I have said that s5 was my least favorite Flash season but I still think it is good enough to watch if I ever do a full marathon. Frankly, if I were to pro/con everything, s5 certainly had enough pros to keep me watching.
Really, I would only tune out during the Cicada storyline. Other than that, it was a stellar season. Maybe better than s6.