Not a HUGE amount of time, just enough for the plot point to actually MAKE SOME FUCKING SENSE. As it was, the entire Casterly Rock/Highgarden sequence was so full of huge plot holes it feels like the writers don't even give a shit anymore. Next episode we're going to see Dany flying on her dragon and she's going to turn her head, and see Euron's ship is flying through the air after her with him screaming like a moron. It would make about as much sense as the magical teleportation that went on in this episode.In what possible universe does Grey Worm at Casterly Rock merit some huge amount of time?
It's not so much that they should have spent a LOT of time on it, but they could have spent a liiiitle more time actually setting things up so it made sense. And, hell, just write it so it wasn't fucking stupid? Like, instead of the Lannister army magically teleporting hundreds of miles across the continent to seize a bizarrely undefended Highgarden, have the scene be Tarly turning the Tyrell army against Olenna and seizing Highgarden and capturing her. It would only require a slight change of costumes and a couple of additional lines of dialogue for the scene to be played like that instead of how it was, and it would have made 1000 times more sense (as well as actually tied into the events of last episode ... as it was, what was the point of having the scene of them trying to turn Tarly against Olenna, if they are just going to take care of Olenna with their magical transporting army? Yes, yes, I know Tarly was WITH that army, but all of those soldiers were Lannister soldiers, so they just ignored the whole plot point of betrayal they set up just one fucking episode ago).