Well...I could see the introductory battle taking place in one realm, Earth being shown, Asgard being shown, obviously the Dark Elves' realm...and some sorta relations with the Frost Giants, so that's five right there. Three others could be shown for a few moments if I'm right about a pursuit through the realms, and then Hel, I could see being shown at the end to set up the third film with Surtur.
I mean...you have 120 pages to fill when you write a film...it's a LOT more than people seem to realize. Each scene is only a few minutes long, so that's still AROUND 40 scenes, at least.