Does this swordsman pose have any significance? Does this pose of raising your sword with your right hand have any significance? For example, is this a famous pose used by a real life legendary swordsman? Both Zoro of One Piece and Erza of Fairy Tail have used this pose.
I don't think it is reference to anything specific since it's overly common whenever swords are (and sometimes when they aren't) involved in media. 

In general:


it looks cool 
it's usually a show of triumph by combining display of:


dominance (as other poses that make body "unwrap") 
combat impracticality (no one is doing this in the middle of it)



tvtropes call it StabTheSky.