Why would you doubt that the events of BvS will have changed Bruce? It's not possible that Superman's death changed him because it literally did change him, as is evidenced by the things he says at the end of the film.
I only doubt it because Snyder has a hard-on for a Batman that acts like an ******* towards everyone, and wants to base his Justice League off of Watchmen. He could change, and see the good in humanity like he says in that final scene, but im not sure if i trust Zack Snyder enough to stick with something. Ill believe it when i see it. For now, you're right, but i have reason to doubt it when i see his murderous behavior in a future Justice League scene (if it is indeed
that).
The resolution to his fight with Superman (code name: 'Martha') changed and affected him by shaking him out of his misguided rage and mindset, leading him to do the right thing instead of the wrong thing he was hellbent on doing. Superman's death changed and affected him by inspiring him to be better, do better, and to believe again that "men are still good". It also inspires him to seek out and join up with the other metahumans -- something I'm willing to bet the Bruce we saw in the first half of the film would never have considered or agreed to. He also says that he failed Superman in life but won't fail him in death, and I'm sure he means it. (Remember that if Batman had actually been acting like Batman instead of the shell of himself he had become, he would have instead been focused on Lex's nefarious activities and could have potentially stopped Lex from successfully creating Doomsday -- and Superman would have never been killed)
The Martha bit at the end of that fight changed absolutely nothing. Ill give it to you on the bit where Superman dies. It seems like it changed him, for now. But what does Batman do, immediately after the Martha scene? He flies over an area and blows a bunch of people up. Flying away with an expression on his face that feels like he's either satisfied or it's just another day at the office. "Meh, they were in my way" attitude. Wow, that really changed him!
The death of Supes probably does inspire him to look at the positive side of humanity again. But it didn't inspire him to seek out more metahumans. He did that because of his dream/memory where Flash tells him to find more of them because something is coming. Bruce thinks he was let it on a secret about the future. He's paranoid and getting prepared for something that may happen. It's not because Superman died, and he's all inspired.
Hopefully Superman was the one who helps him get back to the old Batman. But i have a feeling he's still going to act like an ******* towards everybody because Zack probably thinks it's cool as hell.
Whether or not you liked how those character moments were portrayed, I don't think there's any sense in doubting that he changed, and all signs point to those changes sticking in future films. I'd be pretty shocked if all of that was somehow undone when we see post-BvS Batman in JL or other films and he just reverts back to the crazed and reckless vigilante he was at the start of BvS.
All signs point to those changes sticking in the future? Really? How's that? Of course it's logical to think that future Batman won't be killing or branding folks, but since when does Zack Snyder use logic? Anything is possible with that guy. Especially with his Watchmen comments.
As far as Bruce/Batman still acting grumpy and being somewhat of an A-hole, I think we can still expect to see that side of him to a certain extent which makes sense. He's not going to all of a sudden turn into a guy who's heart is filled with sunshine and rainbows. This is just kind of how Batman is anyway in terms of how he interacts with other people and other JL members, even in the animated series. He's the "straight" man of the group in a way, with somewhat of a no-nonsense attitude and a gruff manner to him. Plus, he'll be the oldest and most experienced member of the JL, and will be surrounded by a few less-experienced and more bright-eyed individuals like The Flash and maybe Cyborg. I love his dynamic with the other JL members in the comics and animated stories, so I hope that carries over into the JL movie to an extent.
Yeah. That's fine, but we have Geoff Johns writing a Batman movie where it may be a prequel. You know, when Batman was apparently more traditional Batman. But Johns likes to write Batman like a childish ******* who wants everyone to bow down to him. It could be a prequel or a sequel, we don't know yet. Im willing to bet that Justice League Bats will be the leader but a total pain in the ass to work with in every way imaginable. Im sure Affleck will nail this and look badass, but A-Hole Batman can be exhausting and unlikable after a while. Im kinda looking forward to Flash or Cyborg poking fun at him.
The only glimpse of a compassionate Bruce that i saw in the entire movie was in the first scene where he saves the little girl and hugs her. If they can expand on that, this could be the best Batman ever created for the big screen. But i still have that feeling we will be looking back on this era, years from now, and going "Yeah, he looked badass, there was potential, but it was kinda just a Frank Miller meets Geoff Johns Batman mixed together, with some colder s**t thrown in the mix.."
Suicide Squad could be the beginning of something great for him. But it could also be a ruse. He may save Harley and then do something ridiculous to another character later on in the movie. It's a trailer after all. I bet Joker is not even a character the Squad is after. I have my reasons for doubting all of this, when Batman v Superman gave me a good enough reason to be skeptical about...everything. Especially with characterization.
EDIT: All Batman/Squad scenes could be in a flashback. What bothers me is Bruce could drop the killing b.s, but Joker still won. He still lost, and he can't take it back that he let himself become one of those people. If he stabbed Superman and then found out who he really was, that would make him as bad as Joker. But if it wasn't for MARTHA, he would have stabbed him. If Superman yelled DANA!!!! SAVE DANA!!! I f'n guarantee he would have plunged Supermans chest with a spear 1 second later. It's all chance, and it does bug me.