To address the biggest critique I've received so-far, up-front, people seem to be wary of having a healer that can take damage while being next to the tank, and worry that this would result in a Healer that is OP due to survivability. The way I have proposed to balance this is by
A: Putting the GEO in the way of greater damage
B: Relying on positioning for buffs that leave the GEO vulnerable if they fail positioning
C: If the GEO focuses on its limited self-healing and defense to survive, they will not be able to keep up healing on their Team, so even though they may survive some things other healers are not able to, they have to be more attentive to their team to maintain healing, and if they over-extend by becoming overly-reliant on their higher defense, they will find themselves overwhelmed. In this way, the heavy armor etc. becomes necessary, since this class is intended to not play like the other Healers. Assuming the heavy armor and ability to take some hits to be OP based on conventional Healer expectations should be mitigated by how this Job would be played.

You may have points or thoughts that I did not consider in this regard, and often, in design, the Achilles heel of a concept is that I am blinded by intent, and people with a different perspective may find exploitable mechanics in my design. I encourage you point those out. That's what this is here for: to talk about and play around with as an idea.