Geomancer tank?

[Tex_Mex]

I really like the idea you are going for with this line of thought. My favorite incarnation of an "Evasion" tank is the Warrior class from Tera Online. Though tanking in that game is VASTLY different from this game.

The biggest issue I see with an evasion tank in FFXIV is how encounters are designed. Tanking in FFXIV really only has a few aspects: 1) Fluff damage mitigated by armor, 2) Tank busters mitigated with skills, and 3) A requirement to keep enemies as still as possible.

Any tank in the game must be able to handle all three of those aspects due to how the other classes are designed. For instance, a ranged tank that wants to keep distance by kiting or re-positioning is going to frustrate the crap out of any melee dps in the group. This is exactly why the 3 tanks we have all have big heavy armor and are melee oriented. This type of encounter design is, IMO, one of the largest flaws in this game. It heavily restricts job design and leads to many jobs just feeling like different flavors of the same basic design. It also means that a true "evasion" tank is not really possible, as a 50% chance to dodge wont matter when that big tank buster comes around. You're gonna die without a consistent mitigation tool.

I say all of that only because it is important to remember these limitations when designing a class. If Gemoancer is to be a magic oriented class with light armor, then the class will have to have some skills that will make it equivalent to the other tanks.

1) Fluff damage mitigated by armor - If the class is going to be able to effectively tank in lighter style armor, it is going to need a mechanic (like a stance) that drastically boosts its armor class, so that it can survive the fluff damage from trash packs, adds, and such.
2) Tank busters mitigated with skills - The easiest to implement by far. Just need geomancer skills like Stoneskin etc.
3) A requirement to keep enemies as still as possible - Here is where things get tough. This requirement means the class basically cannot be ranged. If it uses magic, the magic needs to have no cast time and be melee ranged, or it needs to be magically buffing weapons or weaponskills.

As far as design, I really like the Geomancer from Final Fantasy Tactics. A one handed axe and a shield would be perfect for a tank in FFXIV, and also add another shield user to the roster. The job could focus on fire/earth elements to buff their damage/defense.