Yeah they really need to work with this. I posted this in the spoiler thread I think? Or here? Either way, since nothing is technically mandatory, the game has to pepper in small plot details into basically every big story event. So even when you get one geoglyph and one regional phenomena, you already know that Zelda wound up in the past and is now part of that same Imprisoning War she talked about while wandering the cave with Link in the beginning. Pieces start to get connected really quickly to the point where what you wind up discovering through later memories, while cool imagery, is never this revolutionary discovery.
My favorite and most memorable parts of TOTK were the very end of the game, the end of the geoglyph quest, and, most of all, the first 5 hours; basically from "Nintendo presents" to when you get the Paraglider. I don't think that's an accident; the pacing is controlled, moments hit exactly when the game wants them to hit, and the story is the most impactful. I know going straight to Lookout Landing isn't mandatory, but it should be, especially for a sequel that takes place in a mostly unchanged Hyrule. It reintroduces old characters and re-contextualizes the giant world you may have already spent 100+ hours exploring. Anything to help invest you into its world. Best part is, despite the opening's more story-centric focus, I never felt the game limiting its scope for the sake of a tutorial. I was doing all the same things I would be doing once the guard rails are taken off and the world completely opens up. The Great Sky Island isn't technically linear, but it feels best serviced to be and the experience never feels like it sacrifices freedom, because your new abilities have such widespread usage that are all applicable at any given time; your imagination is already unlocked.
If this "open-air" style of Zelda is truly the future then they definitely need to fine tune exactly how we discover story moments because it's just entirely too easy to rob yourself of the story's agency by finding a late-story geoglyph and spoiling part of that ending for you, and maybe revealing key info without a significant build. Maybe geoglyphs should've appeared one at a time, maybe the game could've constructed a more linear story and left the freedom to the mechanics, shrines and town quests. Progress the story with a completion meter or something.
100% agree with your suggestion that just small dialogue changes would've gone a really long way to preserve discovery. Love the sage idea and I especially love the Impa idea. In fact, since she was the harbinger of the geoglyph quest, perhaps she should've been more involved outside of following her to the Forgotten Temple.