A valiant and interesting analysis I gotta say.
However my point was that it seems you will justify "fluff" if it serves what you deem to be dramatic or in this case thematic purpose.
That's not the case. If it serves that purpose, that means that it isn't fluff.
For example, yes the finale is about coming together as a team, so now that means 30 minutes of thor swinging his hammer and iron man opening up his palms and black widow twirling her staff is going to be all seen as necessary cause it's driving the team work point home. Could that scene have been half as long under a "better" directors edit? Probably, would the film have been better received? Well that depends on what people define as a "better film experience".
I disagree. I can't think of anything in that sequence that could be cut out and wouldn't diminish the rest of the sequence. Everything there either worked towards the themes of the story, gave room for a little character moment that kept us invested in the action, ratcheted up the tension and stakes of what was going on, or just straight up moved the plot forward. I can't think of anything in that sequence that I would call fluff.
Further, that fight could have started with everyone getting to the city at the same time, including banner and cap telling them how to contribute(instead of half way into the fight).
I disagree. The whole team coming together at different times from different places serviced the theme, it dramatized them coming together as a group and being stronger together than they were before. It would have bee a lot less dynamic and a lot less satisfying if they all just showed up at once.
That structure was also confusing, did the tide turn because of banner or because they were still infighting and after the team work started they began winning...
The tide turned because:
1) Logically they're now working together with a coherent strategy instead of everybody just kind of doing their own thing, as well as all of them being there instead of just some of them being there.
2) Thematically, it represented the whole point of people being stronger when they work together.
Speaking of which, a berserker hulk on the air ship, I suppose that had it's point to be sure, but why the awesome fight with Thor...
I thought it was the best part but I'm not seeing the story point of those two clashing. However I'm not going to ask you to address it this isn't the place.
I'll address it anyway because it will only take a second:
1) Logically, Thor is the only person on board who could fight The Hulk, and somebody had to.
2) Thematically, showing the team at odds with each other and how that hinders what they want to do drives home the point about team work and community.