@Nosfentor
Yeah, that's **kind of** wrong. The first 4-5 nodes you want to use a different team on every node because only 1 toon will strike the last blow, so 4 of each squad will have bonus turn meter at the start of the next fight. That extra turn meter is always helpful, but even more so because you don't have Speed mods for some of the toons that rely on speed (Wedge, Biggs, some others).
After the first 4-5 nodes, then you can then use DN, Vader, Palp, Dooku & ST for the nodes 5-10 or 5-11. DN lead and Wedge lead are 2 of the 3 best leads for GW because they give their squads constant healing with every attack. Your Sith are more developed than your rebels, so you're making the right choice.
It's good to leave leadership abilities at level 1, like you did with Leia, if you don't plan to use them, but there are some other abilities that might need to be upgraded. It says your Nihilus is only 39% upgraded for abilities. Is that right? Anyway, Wedge's leadership should be fully upgraded, and other than leadership, Leia & Biggs should be fully upgraded.
You're a bit lacking in Stun-focussed characters who aren't Sith. When you swap out your DN team or it gets defeated, you'll still need Stunners for certain strategies to be successful.
I'd put some effort into R2 and Old Daka.
Long term, Resistance is good for GW once you get a zeta for Finn because the constant TM gain + Expose makes it possible to rip through a lot of enemies before they get their attack sequences rolling. You'll need Rey and Resistance Trooper for that to come together.
I guess I'm curious which GW teams are beating you, since you don't seem to have the problem that a lot of folks do when they struggle with GW - 3-5 gear11 toons and no one else with gear above 8.
If Darth Maul teams are giving you trouble, get Plo Koon (and work on r2, but you need to do that anyway). If QGJ teams are giving you trouble, try picking up Ventress.
But mostly, I think having multiple teams with pre-loaded TM is going to help, because then when Nihilus isn't the right counter to an opposing squad (or when you need to throw in a suicide squad against a tough opponent) the enemy won't wipe out your B team before it has a chance to go.
A lot of people have problems with that - your real advantage is having TM left over from the last fight, but if you send in a suicide squad against a tough opponent and the suicide squad doesn't do enough damage, then you lose that advantage because your opponent will now have TM left over from beating your SS. But if you want your SS to do serious damage against a strong opponent, they're going to have to get in a bunch of attacks before the opponent can go - and the only way to do that is either with Stuns or with TM pre-loaded. Your stunners are on your main squad, and you've got no TM pre-loaded if you're using your Nihilus team from Node 1.
So, although I see some things you could improve on your roster, you might find that managing TM helps you a lot right away.