That’s the thing groups do want another AoE stun over a single target one. You can stun an important mob in a group with an AoE stun the same as you can a single target one. Generally speaking it’s not about how long they are stunned, it’s about stunning to interrupt.
If we got Shockwave baseline, you can still talent to Stormbolt for fights like Jadefire or Conclave. AoE stuns generally don’t work on Conclave because if the raptors are that close they can’t be CC’d. This is why talenting to Stormbolt is useful, while having Shockwave baseline is still usable on a single target as well.
Of course they wouldn’t let you have both which is why one should be a talent and one baseline. AoE group stun baseline, Targeted single stun with a longer duration as a talent (you can always adjust CD length in PvE Vs PvP).