Numbers can change how a class feels.
Chain lighting in my opinion is a defining spell for elemental shamans. It is so satisfying to cast and use. But it’s been nerfed to oblivion.
There is no reason to cast it outside of AoE and even then it’s not that great.
In classic it gave us something awesome to cast when we got a clear casting proc. Which is cool. You hear that proc and now I get to cast this hard hitting spell. That also has an awesome animation and sound while being too mana intensive to cast off of CD.
And looking at the changes it seems like Chain Lighting was nerfed into the ground (also taken off of MSW for enhance) because they decided to giga buff fire nova.
Fire Nova the far clunkier spell to use basically lost no spell power and now gets +35% damage in the tree. They made fire nova shamans best damaging spell for some reason.
By just moving numbers around, nerfing fire nova and moving the damage to Chain Lighting you can make the gameplay more interesting. It will give us something awesome to cast when we get that clear casting proc, even giving us some decisions to make (do I cast CL now or LB with my proc?).
You also give enhance a reason to cast it too. You could even put it back on MSW
Numbers can dramatically change how you play a class