Every professional or developmental league in the world other than the NHL (AHL, ECHL, junior leagues, colleges, high schools, European leagues, etc.) requires visors. Every single player now coming into the NHL has worn face protection. It's not a big deal for them to simply keep doing so.
And fighting has nothing to do with wearing visors. People made the same argument about helmets. Fighters can take them off.
What it HAS to do with is protecting players' eyes, and even their lives. A slapshot or a wayward stick doesn't give a damn how tough you are.
As Jo Innes points out at Backhand Shelf, a visor probably saved the eyesight and the career of our own Danny Paille:
http://blogs.thescore.com/nhl/2011/11/16/the-quiet-room-visors-yes-visors/