Sometimes I do wonder if the audience being left in the dark so much in the first act works well for audiences first time watching it, going in blind per se, but doesn’t really work as well for multiple viewings. You can imagine how cool it must’ve been for audiences to have each character slowly be revealed to them after not seeing them for 3 years. But the slow reveal of the mystery feels a little dull to me upon rewatch. That might come down to pacing issues moreso than the narrative POV, or me having seen the movie so many times, but I still find ANH and ESB engaging throughout despite that.
Personally, I much prefer movies where we see the planning stages of the heist/rescue/operation/whatever before we watch it play out. There are many great bank robbery or prison escape movies that do this. I find it way more interesting to watch the operation play out when I know the logistics and possible contingencies in advance. Watching the operation play out when I have no clue what the plan is or what possible dangers or contingencies exist usually makes me feel like I’m just watching an arbitrary series of events. I don’t know what things were improvised and what things were part of the plan.
And it’s not like this is a foreign concept to Star Wars. In fact, in ROTJ - the very same movie - Mon Mothma explains in detail all the parameters of the Battle of Endor, and tells us who is doing what and what obstacles need to be overcome. That makes it way more interesting to watch as the events unfold, so we know what goes wrong and what goes right, what things had to be improvised, etc.
But I think with the Jabba scenes, as you said, Lucas wanted the excitement factor of slowly revealing each main character to the audience. Lucas probably thought that a scene with Luke, Leia, Lando and Chewie on the Millennium Falcon, looking at a holographic map of Jabba’s palace and discussing the plan, would probably not work as well dramatically for an opening sequence. But it’s still what I would have preferred.