I played through the entire series as a sniper and had no problem in ME1. The only thing is, in ME1, you have to kneel down to steady your aim. And you probably also want to make sure your party is ready and able to be aggressive. Being a sniper with Tali and Liara in tow is probably not a good idea, and you may have to throw a few commands here and there to keep your tail covered, but I never regretted specializing as a sniper. I barely used any actual skills of my own in the first game. Not in combat at any rate. It became more useful and viable in the sequels in my experience though