Tie GL Rey to the Resistance

No. 

Absolutely not. Her kit is good because it's flexible with all light side. Also, RIP Ben Solo.

Turning off DI is probably a bit much.

That said, she shouldn't be BETTER with Non-Resistance which has always been an issue w/ her kit.

I'd say Buff Resistance Synergy w/o completely changing her kit.

Ideas..........

1.  Ultimate  =  Change from 6% Per Character's turn to something more like 4% per Character,  Doubled for Resistance.

2.   I'd honestly change her full team DI to something like Reduce Damage by 90%.
    She is kind of lame at times when turn after turn you go & the fight just drags on w/ you doing basic after basic just waiting.

3.  Lifeblood  = Bonus Protection to others goes from 100% of her loss to .......    75% & Double if Resistance 
     Change from 30% Per DR & DmgBonus to 20%, double for Resistance.

4.  Wisdom of Sacred Texts  =   Change  40Master, 30Speed, 30%MaxHealth down to 30/20/20.   Doubled for Resistance.

Doesn't change her kit or how she operates at all.
Just makes it so she might actually be equal in power w/ Resistance v/s loading her up with Top of the Line Jedi/LSUFU.

Legendary Genral Leia for the resistance, much easier

Rey is the best designed GL in the game. Absolutely not.

How are the Resistance not a legitimate faction? You have two (technically three) solid leaders for two whole squads. A faction like Gungans only has one squad. Imperial Remnant has an army of leaders with barely any troops.

People still drop battles to Zori teams. Rezra is a GAC block to people without Leia, Malicos, Rey (Dark Side), etcetera.

Your solutioning is also curious. Completely alter the kit and change the viability of a several years old character, to buff an equally old faction. Sounds more like you dislike Rey teams and are advocating for a nerf masked as a faction buff.

No.