"I want to be a Tank, but I do not want to use a Sword and Shield."
- You Want to be a Paladin that can use any weapon and not just a sword and shield.
"I want to Tank while being an Archer"
- Although it seems abstract, You can have your bow equipped along with your Archer abilities. The Paladin Skills will help you play your role as a Tank.
"Kay thanks."
I believe this would sum up what is going on. Yes, the Archer Tank seems so ridiculous, but it is how free the Job/Class System would be if Cairdeas's suggestion is implemented.