I honestly think the reason that people find the Blitzes so hard is that Street Fighter isn't as popular as it once was. When FFVI came out Street Fighter was still extremely popular and most people that played FFVI had also played Street Fighter so doing moves in Final Fantasy similar to Street Fighter wasn't an issue. Now-a-days games that use Blitz-style moves are not as common so the general population is not used to doing Street Fighter-style moves.