I doubt that the original plan was good, though certainly this super-rushed wrap-up will not be.
A good plot in an action series or dramatic series isn't simply a matter of intense stuff happening. This story progressed only very slowly when it progressed at all.
I'd rather assume in good faith, but yes, the chances are slim.
There was a lot of errors that result in axed series.
MC and side characters were deep as a puddle, the setting had holes (nobody would live anywhere near that place, even with cheap rent and the prices of other things countered the rent, government didn't airstrike the whole city), power system didn't focus on making the plant aesthetic work, early test arc, monster of the week...
The list goes on.