Turn 6 exploit?

[ispano]

Not all mechanics are there to save you. You can also argue the briars are there to reduce the space of the arena you have while dealing damage to people standing in it. If LoS wasn't a valid method, they'd long fix the run through for other casting skills like Slipstream, Inferno Howl, etc. You can't run through Mountain Buster or Ifrit's flame breath so I think it belongs to a different category of skills.
At the end of the day, do whatever you want OP, it's not an exploit.

Actually, no, they likely wouldn't. That's sort of how SE is with these things. Unless it's a serious exploit, they leave it so as to not "upset" players who do it that way and make them learn the fight differently. Also you could run through Ifrit for Howl on Extreme. So exploit, perhaps not, but that doesn't mean it was intended.