Haha, yea, I know, I just don't get the Spiderman love. I didn't grow up with comic books, I've never read them, I dunno. Maybe that has something to do with it. Every Spiderman movie I've seen has been cringe worthy. He's just not my guy I guess.
As for what I expected, I dunno? Like I said I don't know any of the source material. I just thought there was a Civil War 2 coming, then I found out there wasn't, but there WAS more Avengers movie coming. So I kind of expected a reconciliation at the end since they would be teaming up to fight Thanos in the next Avengers, right?
But your post did clear up the questions I had. I assume having two groups of Avengers will be a continuing subplot into the Infinity War movies. As far as Black Panther, I may be ignorant of the comics but I am informed just enough to know that BP has his own movie coming out so I'm not detracting from Civil War at all for not exploring his backstory. I'll be sure to see his movie when it comes out as I liked his character.
Anyways yea, I loved the film. Avengers 2 was a big disappointment for me and I wasn't surprised to hear a lot of comic book faithful agreed. I had a blast with Civil War, it felt short honestly, which is strong praise for a 2.5 hour film.
The entire film (and all others) all leads to one thing....ultimately coming back together to defeat Thanos. This is just a piece of the puzzle. We all know generally how it will end but when we look back on it in 2020 I guarantee tears will be shed. We are looking at 12 years worth of quality movies. It was so well thought out and planned that we can't help but get attached to it.
Now back to your point, there are so many heroes involved that you can't help but try and find reasons why they shouldn't working together all the time. Example, in Thor 2 I kept thinking to myself, "I know this is a Thor movie, but he may need a hand on Earth because the aliens of really messing up London".
You have the team split into two ideologies. They just have differing opinions on their powers. They don't hate one another but have enough reasons to keep from one another. Cap is now in Africa with Black Panther and they got everyone out of jail. Winter Soldier is out cold (no pun intended). So we now have some type of ground work for a villains reason to attack Wakanda. I have to imagine backstory will be only a third of the movie since BP is established.
Thor 3 is defending 2 Infinity Stones (I actually feel like the black dude who watches the galaxy has a third). Thanos is looking for stones and he (or a hired villain) will try and steal them. Hulk will somehow make an appearance but you have the two strongest guys out in space away from the dispute. Because Loki has ties to the Chitari and they have ties to Thanos he is close to this story line. I forget which movie it is but Thanos flat out said he would have to go after them himself. It all starts here IMO. Ragnarok is supposed to be a real bloodbath. I doubt they kill Thor but atleast Loki will be finished off, concluding that storyline. As of right now, he is disguised in power and I can't help but think he and Thanos have an agreement in place for the stones.
GotG is off in their own world with a stone and maybe one other in their 2nd movie. Thanos will for sure go after these personally because this segment of the story is the only part that Thanos is known and acknowledged. Where as the other movies no one knows who he is yet. I have a hunch they go looking for another, Thanos destroys home and they then find some reason to go to Earth. Somehow they will learn about the Avengers and make their way there.
(That brings Thanos up to 4 out of 6 stones)
Back to the Avengers, they're disassembled and working in two different ways. In the Civil War comics, Cap had a underground Avengers team. This is where everything from the true Civil War storyline will overlap with the MCU. They will do their own thing and Thanos will rear his ugly head looking for the last two stones. In a sense Star Lord will Lead him to both of them. In the process, he kills Vision taking the 6th stone. The team finds a reason to unite and Avenge (see what I did there) their friend. Somehow in the process I feel like Cap dies as well at the end of IG 1. Maybe Cap is the one that dies and they protect the last stone. Not sure yet.
His death and the realization of them needing to be on the same page is the payoff from Civil War we will probably get (the main jist from the Civil War story line at its ending). So what I'm getting as is just think of the full universe as multiple issues with one big payoff. Each one is just a piece of the puzzle that ends with a to be continued. The Civil War amongst friends won't need a second movie because the storyline will be in full effect throughout the rest of the universe.
Strange and Spiderman will be off on their own IMO. Spiderman played a big part in the comics and did a nice job here but I got the opinion that Tony wouldn't put a kids life in jeopardy by having him help with Thanos. He doesnt need to help the Avengers and there is a good chance (if done right) the Spiderman charachter will have his own universe. I could be way off.
Strange wasn't apart of the Civil War line and I'm not sure about Avengers in general but it would make sense for him to stand alone (like the in humans probably will). He has had his name referenced once but no charachter intro has been made. If anything he will tie into the inhuman story and maybe some other galactic stuff I know nothing about.
Despite this storyline in the movie being way different than the comics (the reason for the Act), I loved the movie and if you can take each movie as a different issue and look ahead to see where it's probably going you can't help but get excited.
Hopefully this incoherent babbling helped understand why the movie ended the way it did.
Sidenote: I'd be curious to see who Thanos brings to the fight with him. As powerful as he is, the guy in charge always tries to avoid the fight and make others do it for him.