Sure Buddy, the shield adventage is exactly 0.1 sec at 4/4. Seems like a fair trade since mage can block all incoming damage and rogue dies instantly to all spells that deal damage over time such as druid's tornado, mage's blazing ground, bd's bleeds, ranger's bleed, all stacked coz of huge amount of players in one location. Also even if a rogue managed to stay alive, its ability to deal damage to the flag is so much worse than mage's due to low aoe damage, and you cannot really target the flag because of close to 0 resist capabilities and passive just not working as good as mage's shield. It is always more convenient to cry about nerfing something rather than learning the actual state of the game.