Smith was/is not used properly, that's an issue... same as having Helm playing top minutes or having Nyquist and Tatar on the same line.
Smith's usage doesn't diminish Fowler's talent one way or another. Also, over the course of his career Smith's best points per game averages have come when he's played less minutes, not more. So if you think he's going to bud into some offensive force with more minutes you're probably off base. He seems to do better offensively when he's playing more sheltered minutes not vice versa.
I'm genuinely fine with Smith. I like where he's at and what he's doing. But there's a reason why the guy has consistently earned less ice time, and more sheltered minutes, from two different coaches. And it's not because he's more dangerous when he plays more.
At his best I see Smith as an Oduya or a Stralman. A guy who's good in transition, physical, and reasonably good on special teams. But he's probably never going to be an offensive threat at the NHL level. He's 250 games into his NHL career and has never shown an offensive inclination thus far, regardless of how much or little he plays. And in today's NHL a guy who can do all that AND score 30-40 points will ALWAYS be more valuable.