I agree many rpg have mage types in plate armor. Clarics in Aion can use heavy gear sets and are a dd white mage. Look at al the WoW classes and their gear. Two worlds 1 and 2 is another rpg that mage types can ware what they want. I had a guy in full plate with a staff casting spells.

In DCUO same thing everyone is hybird of a melee caster. My choice set up was a flying monk fight tank. And I liked it. They should make clases feel different but also allow to set abilities from other clases. If I wanted to be a pug who can cast fire and have a cure I should be able to.

As i said min/max is not always the right plan of action. And is not always efficient. Everyone working together as a team helps and every little bit helps. Point of mmo or video games in general is to have fun. It should never be about worring if you are "good" or not. I stop playing in parties in ffxi because of all the min/maxing. Gear is so hard to get in the game now and I was afraid of not being good enough and being kicked.