Why do people want SAM to be a tank!?

[Chiramu]

Plenty of MMO's have tanks that don't look like tanks (WoW's Demon Hunters, Monks. SWTOR's Sith Assassin/Jedi Shadow, Rift's...everything basically, rogue and mage tanks etc.) FFXIV's future tanks don't have to look like tanks if SE doesn't want them to, even then, Samurai still makes perfect sense to wear Fending armor still.

They have to ditch the tank, DPS, heal set idea for tanks to retain their unique look for this though. Demon Hunter gear in WoW still looks like Demon Hunter, and the Vengeance gets the same benefit from the Havoc DPS gearset.
This would be a good idea for SE to look into, it would be nice to retain your class image. I don't want my PLD/WAR/ whatever to look exactly like each other.

[Shippuu]

They have to ditch the tank, DPS, heal set idea for tanks to retain their unique look for this though. Demon Hunter gear in WoW still looks like Demon Hunter, and the Vengeance gets the same benefit from the Havoc DPS gearset.
This would be a good idea for SE to look into, it would be nice to retain your class image. I don't want my PLD/WAR/ whatever to look exactly like each other.

This is exactly why future tanks are likely to still share the same fending gear and overall appearance. There is already a lot of different armor classifications in FFXIV, making loot pools very cluttered, and so adding more is a bad idea. There's also a design benefit to tanks/healers sharing their armor which allows people who play those much needed roles to gear multiple tanks/healers. This gives them the freedom to switch tank/healer job fairly seamlessly (barring weapon).

Rather than cluttering the loot pools even more, a simple multi-glamour system would be easier and smarter to implement to solve the issue of tanks looking the same.