While...despite the look of sX(the pic and real bey sometimes give me very different feeling), sX is very different from X and X2.
First, the sword handle side of X and X2 are relatively round, so if this side hit opponents, the attack power would be decreased. But the sX looks like a rhombus, which means the attack can be very powerful no matter which part of the layer hit opponents.
Second, both Xtreme and Impact are fast-moving driver with poor stamina, and are good at smash attack(although Impact is actually terrible), but the new Iron driver is not such a driver. Iron might not move so fast but has better stamina, and perhaps it can be useful on barrage attack.