Did they change it slightly in 5.3? The lightning stream itself looks a bit shorter, looks less laggy when you fire one off and the graphic seems to be a bit more bright and "sparky", looks more electrical than before.
First noticed it while levelling my priest in Wailing Cavers and one of the druid mobs fired one off, so I logged onto my shaman to have a go and it's definitely better looking than pre-5.3.