When Lashley does eventually turn heel, it'll be for the better, because it seems like stars are always more over when they turn from heel to face for the "near-permanent shift". Look at Shawn Michaels. Babyface at first that was getting attention but needed some focus, so they made him a heel, he got a lot of heat until everyone started liking him more, and once they turned him face again in 95 he just skyrocketed. If you can get attention as a face from the get-go, then turn heel for a while enough that the fans start liking you as a performer (Stone Cold, Kennedy, etc), when you eventually turn face, you'll be a big hit.
However at the moment, Raw needs someone to step up in the midcard as a face. HBK and HHH are permanently in the main event scene and Hardy is stepping up soon I think, which leaves us with no solid faces in the Intercontinental race. It seems like they aren't ready to give Kennedy a main event push yet, so he'll win the IC title from Hardy, and he needs someone to feud with. In comes Lashley. With Kennedy on the mic all the time, the feud could be somewhat of "the guy who talks too much vs the guy who's the strong silent type", since Lashley sounds ridiculous lol. Without the mic skills or a strong enough gimmick, you can't succeed at the top, so Lashley isn't ready yet as he's just a strong muscular guy who isn't too bad in the ring.