It probably sounds crazy, but later on you can drop Sharla all together once you've got the game figured out. She can be more of a liability than an asset, she is by far the worst damage dealer in the game. Swapping her out and focusing on quick damage and agility so your party can dodge attacks works just as well or better than trying to use a healer that slows down battles.
True, Sharla can't really put out DPS for crap. But, she partly makes up for it with her Stun + Headshot combo that can Instant-Kill enemies (assuming they aren't immune).
But yeah, Sharla can be dumped if you're in no danger of dying quickly.