My take is that the "let Lachy play what is in front of him" experiment has run its course. I think we despo need Latu back and to stay fit for more than 5 minutes. I think Luai is being asked too often, or deferring too often, to giving Galvin the ball.
Latu at 7 and Luai at 6 lets both players handle the ball equally, Luai can focus on runs and kicks, Latu keeps us straight and he distributes fairly well. Latu also has a direct running game.
Currently with Galvin we spend too much energy trying to guess what he's going to do and where he will go. Yes he pokes through here and there, yes he has try assists but he throws 100 grenades a match with the hopes that a few will land in the enemy trenches. Ironically it's very Benji-like, where the lack of structure starts to hurt his team-mates and although we come hard at the end of most matches, its too frantic. There ends up a considerable lowlights reel to match the highlights reel, when really we are begging for a very modest Cooper Cronk-type performance where 90% of the stuff is solid and boring and dependable.
If Latu was back I'd be inclined to try Lachy at lock, so he can still have his efforts but he touches the ball way less and he gets a bit of defensive starch into his game. Or centres. Failing that, you drop him again.
With Latu out however I don't see what other changes you can make except to ask Luai to take more control and pass to Lachy less often.