IMO, Nightstalker is probably the only class to come perfectly balanced out of the box. It has its tricks, yes, but it does not dominate the other subclasses. It holds its own, and that's what it should be able to do. NS is the one class that just needs to be left entirely alone, while others all could use various (some very minor) tweaks. I agree that firebolts are strong, but I don't think Sunsingers have too much else going for them anyhow. I would hesitate to call for a nerf on them for that reason, or at least not a major one. I think the sheer length of the burn could definitely stand to be reduced.