The Super League side moved from their Willows home in 2012 after 110 years at their former ground.
Former dual-code Wales international Harris, 39, had a 17-month stint as head coach at Salford.
"Growing up and playing against Salford for many years, they were always a passionate club," he said.
Harris told Rugby League Extra: "I think what's been a big struggle for them is the move to a new stadium.
"Part of what was symbolic with Salford whenever I went there was the stadium - although it was creaking, it still had that home feel about it and you're in Salford.
"I'm not sure the new stadium has got that and I'm not sure that Salford, as a club, have quite got the identity which they probably had 10 years ago.
"It's whether they can recapture that identity of what Salford was, because the fans are fantastic.
"If they can capture that identity again, I think that's how they can improve."
Salford Red Devils have lost some of their identity after their move to the AJ Bell Stadium, says former head coach Iestyn Harris.