Rogues are DESIGNED to be able to hide. It's our base ability, and one of the reasons we're one of the squishy-ist classes. A mage can oneshot someone with a fireball from a range after stunning & rooting you in place while continuously damaging multiple targets around you & them simultaneously, but you're up in arms against a class that has to get in melee range and STAY in melee range to finish the job? With all the latency errors and ping throttling these days, it's too easy to get away from a rogue if you even have a moderate amount of defenses.
A rogue with no stealth is a dead rogue... all you gotta do is keep 'em at a distance, and without hide, well... that's pretty much a given. Might as well take a way a priest's ability to heal.
A Rogue's ability to Hide is not an absolute guarantee that the Rogue cannot be spotted. Any class which is within a few levels of the Rogue, and within a certain radius of his/her location, has a chance to spot the Rogue. *That* is a given and has been part of the game since the beginning. And may whatever god the Rogue serves help him/her if the spotting character is several levels *above* the Rogue! When I play P/S, I have to rely on luck (at my character's current level as Priest) to spot and whack a Rogue before he whacks me. I die a lot, but I also whack a fair amount of Rogues, too. You're free to believe this or not. I don't particularly care.
A Rogue can *also* be targeted at a longer range, if the character doing the targeting uses a very simple technique, one which my guild uses when it's practical to do so: Guildie gets killed by a Rogue who pops back into Hide after leaving combat. Guildie doesn't immediately rez, but still has the Rogue targeted, and calls out that <insert name here> went Hidden next to <insert area on map here> and is still targeted. Guildies in the immediate area and grouped with dead guildie can click on the guildie's name in the group, gaining the guildie's target information. They click the Rogue's picture and go after it with torches and pitchforks. Perhaps that's how you're being hit with a Fireball @ 150 yards.
This also works against targets who leave combat and use an Invis pot to try exiting the area or avoid being hunted down.
Bottom line: Park your pet--too many players seem to rely on them far too much in siege, and they're the easiest way to spot a Rogue that's lurking in the viscinity. Avoid using consumables or ISS to heal up or restore energy until you're in a much safer position/place to do so.
And quit QQing about how those poor Rogues are the red-headed stepchildren of siege. They aren't.
Scouts are.