Id argue against a healer not being able to make a scout a tank after being a Cleric in EQ1 and EQ2 :P
What makes a good tank imo among basics of mob control, but more indepth like asking to be assisted on what needs to die first, nothing more frustrating when handing back as a caster than trying to get the group to go for the right mob first etc.
Tanks do lead the way but a good tank is always open to advice or letting someone else lead in effect although the tank may be at the front.
A good tank knows all the classes to a decent level and knows what they are capable of, and how to group with them, for example, nothing more annoying as a Rogue in EQ1 than a tank that refuses to position a mob anywhere except with its back against the wall ! Thats a basic but it can extend a lot and a great tank is knowledgeable
