Starting in reverse order:
I'll clean the OP up when I get actual art for the card, Higurashi.
Seeing it costs 6 quanta of three different elements per shockwave, and a fourth element to get it out in the first place, it's not the easiest thing to just spam and pull off. Even in rainbows, you're going to struggle to pull off the cost continuously, especially considering when a lightning or RT or even just an octopus will do the job just as well.
That's why the card has an element and isn't just chroma; I anticipated the fact it had the one hit kill combo on the card, which is why it's a quartet on a card, being really unstable.
(FYI, the emoticon is called rage candy. It's two angry faces put together >:U U:<. I could just do >:O:< but I'm too hipster for >:O, as you can probably tell by this card in general.)
...Making the card chroma buffs rainbows even more, which, as Higs has pointed out, is not good.
How about making this card use mirror pseudoquanta, or quanta of your mark, Odin/Andre?
That wouldn't hurt decks that would use this whilst keeping the rainbows about the same power.
I just feel that spellslinging decks go in fire, because fire has most of the cards worth spellslinging.
But, yeah, in this case, it's not doing stuff to cards, so it could go in aether, or mirror.
The upped is nichier than the unupped, so that's why it's the upped; I'll save you 1500 precious electrum. Yw.
It doesn't have to be powerful, it just has to be fun. Like SoSeren isn't powerful but it's fun.
I feel the upped is fun, which is why I'm fine with it being weaker than the unupped.
Although, if we were to make the card blessing -> overdrive -> liquid shadow... I feel that's the strongest ordering. Spam +15 | +15 a turn