Doitsuyama wrote that Wedge lead is better (you might remember).
Now I understand it. If you have access to 5-dot-mods faster then your opponents, Lando's +13 Speed will become irrelevant. You see my STH has this +30 speed receiver, but the 1-dot-receiver is only +17.And that is exactly what I find in my arena.
Does your guild do heroic rancor/AAT? What place are you there?
Maybe if you get to a better price category with 5x 7-star chars, it will be worth it.
I am in the lower 20s with my 4 chars, so okay for me atm (reward for heroic rancor is H1-04)
https://swgoh.gg/db/raids/the-pit/rewards/
For Arena, I don't think 7-star-GS will be better then Wedge. Most fights are really decided early, aka can you oneshot someone. And with Biggs, Wedge + another as a help, you probably can.