Dwight is a difficult character to have sympathy for on The Walking Dead, even after "The Cell" gave viewers a peek behind his psychological curtain. He's under Negan's thumb as much as anyone else, forced to comply to survive and suffer any and all abuse heaped on him in the process. However, despite understanding his circumstances, it's hard to care about him after watching him kill and harass characters fans have known for a lot longer. (He also flaunts his theft of Daryl's vest, which is, quite frankly, a look he can't pull off.) Still, Dwight's unhappy loyalties could definitely make him useful going forward, especially if he follows his storyline from the comics. For example: does Dwight betray Negan in The Walking Dead comics?
Indeed he does. In the comics, Dwight is hugely important to Negan's eventual downfall. The show even began to lay the unsubtle seeds in "The Cell" of Dwight's eventual defection from the Saviors. He's had everything taken from him and he hasn't fought back yet, but his patience may very well be running out. In the comics, Negan's persistent taunts (particularly about Sherry, Dwight's ex-wife and Negan's current wife) push Dwight to set up a secret meeting with Ezekiel, Rick, and Paul Monroe. He agrees to take Negan out when the right moment comes.
Having a man on the inside would be very beneficial to the cause. Right now the Saviors seem like a unified force that can't be broken or defeated, every last one of their vast numbers appear to be dedicated to Negan. But while it may look like that to Rick, the audience knows better. Dwight is the chink in Negan's armor and exploiting that could bring down everything. If the show follows the comics, then Dwight is the key.
After his meeting with the other community leaders in the comics, Dwight pretends to be a good Savior while secretly undermining Negan when he can. During the big final battle, Dwight even provides Rick with a major advantage. Negan had been infecting his enemies with zombie-dipped arrows so that they would be sure to die no matter how shallow their wounds. But when instructed to shoot Rick, Dwight uses a regular arrow instead — all while concealing that from Negan. That then makes Negan think Rick's days are numbered, so when Rick finally emerges alive, Negan is taken off guard. This allows Rick to get the upper hand.
After Negan's defeat, Dwight goes on to be a leader himself when he takes over the Saviors, however, he eventually gives it up. But even though he decides not to be in charge, he still becomes someone Rick can depend on when he joins up with the Alexandrians against newer threats. So even though Dwight might not seem like much help for now, he may have very important things to do in the future.