Yes, this is pretty much how I think about each scene and chapter. Very much dialogue first and usually, 9 times outta 10 that leads into a complete chapter narrative that hits the main points of said chapter. In terms of the bigger picture I have a outline that sets up key events in the story that must take place due to A connecting to B then C and so forth.
But how I get to those events our sometimes vague in my mind at first, only with further planning does the picture come clearer but conversational details don't come in concrete form until I start scripting and it usually just flows together
If I was your position though, while looking forward to those cool big events in the story, I would try to make those little moments in between those cool events even more interesting for myself to write. Because if the only reason I'm making a comic was for those big action scenes, I could've just made a quick one off comic showing that scene.
So like if a big event for example sake would be a fight, why should the reader care about the fight at all leaving out the cool factor of it? That would mean they would need to somewhat like the character(s) in said fight. With that in mind think about who your characters are, their personalities, goals, fears and how you can develop them into interesting characters in the story you're trying to tell in which will help lead into those big moments. Really develop them and usually when you're writing the narrative and scripts you will probably feel your characters pushing your story along in ways you didn't expect.
This is where the phrase "My characters did something I didn't expect" stems from.
A lot of the time they help drive the narrative, you're just the one writing it.