I always thought it would be neat to see SAM take up the role of a Tank within FFXI. Back in the days where everyone craved for a PLD (but settled with a NIN if they needed it), it was hard to come by making EXP PT's due to the short supply of Tanks.
I thought about "Well Third Eye is already in place... They could really do something with that, and also SAM has a high level of Parry(A-), so they could sort of tank with Parrying blows and using Third Eye" And it seemed like that was the intention by SE when they implemented Seigan. But maybe people didn't really catch on to the idea? Or it's possible many just wanted SAM to remain a DD.
In any case, it could be possible to still take SAM down the path of a "Tank" by giving them some form of Parry JA/JT, something like "Perfect Parry" kind of like MNK's "Perfect Counter". Also boosting their natural defense and further developing Seigan/Third Eye would help too.
I just thought it would be a neat idea and a way to add more "Tank" roles into the game. Let me know what you think.