At this point doing a rework of SAM (including Potency buffs) would be quite a boost, but quite an undertaking to balance. However, one idea that I've been playing around with in my head is a single boost to a certain skill. I'd recommend a trait at lvl 65ish for SAM that does the following

<title>: Increases the slashing debuff from Yukikaze by X%.

The idea being a simple boost to DPS similar to how DRG enhances BRD and MCH DPS. Now this also means that WAR and NIN are still viable, but the slashing debuff the SAM brings being stronger makes them a good choice for certain comps.