For shamans elemental spec, having the talent give a split ‘select’ option between two variants of the ability would be most ideal for the players.
- Primordial Wave: Blasts the target with the elements & applies flame shock and triggers the lava-burst proc on all flame-shocked targets.
and the other:
- Primordial Wave: Requires flame shock, however bursts the target with the elements for massive damage and triggers lava-burst proc on all flame-shocked targets.
Thus BOTH preferences score a win. 
The 1st would naturally represent to how it use-to function, that many are both familiar & accustomed towards – not to mention find very preferable in a variety of situations.
The 2nd is how it functions currently now – and despite not applying flame shock, has the upside of launching devastating attacks from the brunt force of its blast to those that are flame-shocked — having significantly increased its power significantly with the spell itself.
- If there was a minor rename for one to separate it from the other, I’m sure that most people wouldn’t mind that either (eg. Primordial Blast).
Overall it would also spice up elemental life for changing up their talents and playstyles depending on the fight or situation they’re to be up against.