Thank you SE for...

[Deceptus]

- You have a personal tank LB3 (even better than a tank LB3). Any kind of mechanic coming? Who cares! Just use one GDC! Problem solved! Tank tethers? Pffft, joke! Shared tank buster? Just let me join the fun! Not imbalanced at all.
- You can heal yourself and other people to full in a blink. I don't really care if you don't think that White Wind isn't an issue. A DPS job being able to bypass a raid damage mechanic with Diamondback and then heal everyone to full in one skill is broken. It is. It objectively is.

Boss Ultimate attacks (failed ones) go through Diamondback.

- You are able to withstand a lot of damage from any mechanic thanks to Mighty Guard. Similar to Diamondback, but with more flexibility at the cost of less protection. It still allows healers to shield the BLU in order for him to be able to easily White Wind the mechanic.

Go attempt to tank an lvl 50 EX dungeon with Mighty guard and see how fast you melt. I'll wait, because you'll be back really soon. 40% reduced damage doesn't mean much when you're taking so much due to wearing cloth.

- You can give anyone in the group 100% HP and MP at the cost of some DPS. A healer died and is in need of MP? No problem! Better have a dead DPS than a healer. It's probably less broken than the rest, but having a single target full HP&MP is still not really something you see every day on a Caster DPS.

"Some DPS" yeah, 25%. . . that's a lot. Especially when BLU has low personal dps to start.

It's like if idk WoW for example, we'll use this since it's a big MMO as well, they introduced Death Knight, the first hero class in WoW in the Wrath of the Lich King Expansion (WOTLK), its similar in a way that DK was an agent of the Scourge, an entity of evil but they changed it into an actual class. You could now use your favorite Scourge minions in battle, you could tank and be great at it and here's the thing it was really strong at the start, not to mention it wasn't gated by just doing lvl 60 content 2 expansions ago like Blue Mage. I know they're different games but still, there's always ways to make a class be able to function in an MMO.

Pretty much this. No one would be having issues if BLU was strong, but they're simply not. It would have been better to start strong then reign them in instead of starting weak and have players be disappointed.