Laezel is a better single target damage character but late game shadowheart has so many tools in her bag..I wouldn't want my Shadowheart to be a lesbian, but I was playing as a male character
Elle is a more badass character than Shadowheart though. I'd pick her in a fight definitely. Shadowheart is kinda weak, but I used her as a healer.
Spirit guardians/guardian of faith does so much consistent damage, you get heals, you get great situational spells and status effects, she's undeniably more valuable at the end of the game.
Karlach and wyll are the worst characters unless you multiclass, honestly
Edit: nvm, you meant ellie
Eh