Perhaps one should get past the notion of being a "dedicated and determined sniper" and try to become a well-rounded player. If you're already well-rounded, then just accept that the game has class limits and learn to live with it. It's not going to change.
If you want an all-sniper map, you can always make one yourself and see how well it plays on servers and how many servers play it. I suspect most wouldn't run it because it'd totally kill the flavor of gameplay we have now.
I came to RO from Forgotten Hope which, while a lot of fun, does not include class limits (except in the form of pickup kits). Whatever class is the optimum class for a given job or at a particular point in a map is always the class most people take. Got a map with tanks? Take the class that can drive tanks, drop high explosives, and has a long-range weapon to use over the pistol-packing tank driver or the dedicated AT-class. Got a map that's all close combat? Grab an SMG trooper and forget the longer rifle.
Trust me, class limits are a good thing. If you're really seriously hankering for a sniper rifle, you can always try buying more RAM so you load faster. Or, like you said, follow the sniper around and wait for him to die (while giving him cover).