Quote from OizenX;515453:
Go with Dark Knight, the def boost for pally is so insignificant when you fight anything that hits hard.( High Level Raid bosses)
Taking the pally route is a very viable option when aiming for longevity in a raid.
The closer the player's defence is to a monster's attack power the less damage they will inflict on a player. Lanns with an average of 5k defence (at lvl 60+) can easily reach 7k+ defence with pally transformation, which can match Titan's (7202 atk), Thor, and Ingkells' (7506 atk) attack power; therefore, taking much less damage than a DK with 6k+ defence.
I suck at number crunching so just think of it this way: a player with 4-5k defence will die in 3 hits to a high level raid boss whereas a player with 8k+ defence can tank 10+ hits before dying. Defence is more effective the closer it is to the monster's attack power.
As a spear Lann, pallies can become more reckless and typically spin2win much longer than DKs can because they can take in more hits. Sword Lanns will benefit more from the DK's increase in balance and attack than the pally's defence because they already have great survivability via slip dash.