When will we get the PVP system for PVE ?

[Reynhart]

Probably because Fire III and Blizzard III function differently than Fire and Blizzard.

Do BLMs really use Blizzard after gaining Blizzaga ? And, without Firestarter attached to it, I'm not sure people would use Fire instead of Firaga. Of course Blizzara and Fira would be kept, since they're AoEs.

can’t speak for SMN on this, but I’m pretty sure Ruin II and Ruin III are still separate, because they function differently from one another—one is insta-cast for use when having to move, the other has a cast time

Ruin and Ruin II are separate but Ruin is upgraded to Ruin III

Same for Aero I > Aero II and Aero III: one is single-target, insta-cast; the other AOE with a cast bar.

But Aero II lost its cast time so that it could replace Aero. However, Stone lost its heavy effect to be replace by all subsequent tiers.