Why was Doctor Who serialized from 1963 to 1989? Partially because that's how most scifi shows were aired at the time, but also because the stories they wanted to tell couldn't be told within one or two episodes.
Flux is a story that didn't need six episodes. Most of the content doesn't even need to be here. Instead of inserting things that are mentioned every episode only to pay off one tiny, insignificant detail, maybe find a way to get to the payoff without cluttering up the rest of the narrative. They should have had that first Sontaran episode and the Weeping Angel one be standalone, then have the Sontarans come back for their original plan for a three part finale. No 19th century miner digging tunnels, no weird crystal people, just a nice tight story.
You know, for a universe-ending event, there sure doesn't seem like there's a rush. They just make it more confusing by making the Flux affect the past, but not really? They introduce too many new things, people, and worldbuilding to keep track of. Plus, the editing is a bit wonky.
This had some potential. If only they'd trimmed the fat and kept a focused vision, we might have had something halfway decent.
