I think for the fans the ending was most important, which is probably why people only generally familiar with the first film might find it a tad dull
Not going to spoiler this, as I imagine anybody who wants to see the film has done so by now, but re Egon having no lines, I suspect it was in part due to trying to get a deep fake to act. Rogue One had a big problem over that with Tarkin - he was pretty convincing, until he opened his mouth. I think having Egon talk might have risked breaking the spell.