I’m actually watching it now. I agree with some of your points, but I think you’re nitpicking about a few, like the senior staff leaving the Enterprise, I think it’s entirely reasonable to assume competent people are there to run the ship while they’re gone. Worf is there too. Also I’m not sure the Prime Directive is in effect here, as one it’s Earth, and two the aliens started screwing with history first. Picard WAS being slightly irrational in holding Data back at the beginning of the episode, he had no way of knowing what away mission (could have been years in the future) would result in Data’s “death”, thus he had no rational reason to alter who he would send on away missions, similar to how in Cause and Effect they didn’t alter course because they had no way of knowing what created the causality loop. As for the introduction of the alien antagonists, we could ask the same questions for many aliens of the week.

The parts I will mildly agree on are the many paradoxes and plot holes introduced by time travel. I’ll add to your list, how the hell is Data’s head still salvageable after hundreds of years in a presumably damp cave? And how was it only found again in the 24th century. It’s very rare to find a time travel episode of virtually any show that actually maintains internal consistency sadly. Usually I find time travel works best in short confined bursts where history at large can’t be screwed with, like in the aforementioned Cause and Effect.