Currently there are two obvious paths SE can take with SAM (And BLM). There are other solutions yes, but these seem to be the most glaring.

First Option: Give them useful raid buffs and admit that the concept of a selfish DPS class seems to not work in it's current system.

or

Second Option: Increase their personal DPS by a wide enough margin to make them an engine of destruction.

I made a post about just increasing their slashing debuff recently (a third option) essentially letting them be selfish, but still helping the party considering all tanks are Slashing based. A sam would be wanted in any party that also had a warrior due to their damage focused attitude. If the party also had a ninja it'd make a very vicious pairing and likely balance the whole build out.