Gaffer Tape said:
But, Gaffer, Anchorhead will scoff. Those are the sequels. They're just ridiculous, they represent a different mindset than the first film, and I try to pretend they don't exist!
I don't try to pretend they don't exist. I have little or no interest in them these days, but I'm aware of the story continuation. That's why I don't make statements like "Those are not Star Wars films", "those are not canon", etc, etc. They are. They're just Star Wars films that I haven't seen in a long time, following a story line I don't care about. My issues regarding Lucas and his attempt to alter history are a separate matter.
For the record, I think Empire has some fantastic moments. I may get the 06 DVD of it before too long.
Regarding your post, are you asking something specific or just pondering the less-than-consistent portrayal of the Stormtroopers throughout the series? It seems to me that they were a substantial threat in the first film and less so in the second & third. As far as Phantom goes, I don't remember seeing any, which is just my lack of familiarity with the film. I can't speak to their threat level.
As for Vader, I think his level of threat and\or power was correct for the story in Star Wars. He was a military member with little regard for other people, he was highly skilled, and had a questionable past that was enough to keep other military personnel somewhat distant. However, he wasn't the be-all, end-all of all things Empire. He wasn't beyond authority. He answered to other ranking members, who did sometimes challenge him. I thought that was a perfect balance.
He was morphed into an almost superhero state as the series went on, which to me felt out of place from the first film.
Ben gave up because a loss was nearly inevitable. Plus it was the necessary choice for the mission to succeed, or even to continue at that point. Earlier in the film, Ben tells Luke that "the droids would now be in the hands of the Empire". By sacrificing himself, he was trying to prevent that from happening at that point in their mission.