I was flicking through my R&D menu a few days ago, thinking I had fully upgraded all my weapons and stuff (except Grenades, that still had 2 '???' spaces left) when I accidentally pressed the Down button. And there were MORE upgrades that branched in different directions. Definitely tripled my 'this is awesome' ranking. I love how every weapon has a story too, it's not just different stats for different weapons.
I agree, snipers in optimal situations are pretty hax. As you can see by Catherine above, she has a weapon where it's pretty much impossible to miss, because the 'hit circle' is so teeny. You do come across some areas where long-range visibility isn't very good (stuff like trees and w/e blocking the way), and snipers have like the lowest Action Points of everyone so they can't move very much, so it balances out a little. I've also come across one particular 'named enemy' that had the uncanny ability to dodge pretty much anything I threw at him. Still, they're a great class when nothing is blocking them.
Don't know if you've unlocked 'Orders' yet, but some of them are really useful. 'Retreat' has probably been my most-used one so far, partly because of the snipers :P I just leave them out somewhere, then when I Occupy someone's camp (with a lone Scout) I get people to retreat then re-summon them at the just-captured camp. Only uses 2 CP to do all of that, where it would likely take more than that for the sniper to either run there themselves or run back to the first base to 'retreat' then get re-summoned. Sniper Support and Mortar Support are great too.