Then there is the whole Finn and Rose sub-plot where they try to get a codebreaker. Their efforts are worse than useless. The codebreaker somehow figured out that the rebels were sneaking away and tipped off the First Order. (I really don't know how a codebreaker could figure this out; Finn couldn't have told him because Finn didn't know either.) The rebel plan to sneak away was working until the codebreaker tipped off the bad guys, so something like 90% of the surviving rebels died because of that codebreaker guy.
When you see it again, you will notice that as Finn and Rose are flying away on their mission, they get a call from Poe who tells them that the Vice Admiral is evacuating the ship sending off the pods, it's clear that the code breaker hears this as they pan to a shot of him.
And why did they take the risk of the whole codebreaker thing? Because the Vice Admiral didn't tell Poe that she actually had a plan, and she went out of her way to let him think she had no plan and everyone was going to die. Was this to "teach him a lesson"? Makes no sense, and that lesson came at a horrific cost.
Her opinion of him was that he was a reckless fly boy who was off the handle and would have probably rejected the plan, I think she was banking on the fact that we would at least fall in line with authority and not do what he did, I feel he thought he had a better plan anyway. I agree with you though, this part was a little "Gilligan's Island-ish".
But seriously, Star Wars has always been a soap opera in space, the writing/plot has never been really great, it was always the special effects/creativity/imagination that was such magic.