This is the only upped nymph I own, and this change won't be enough to make me use it. In a mono rush, I'd rather play pretty much any other creature. In a rainbow, I'd rather use anubis. And in a mono, what are you going to quint, anyway? Spiders? Sparks? Itself? As others mentioned, it would actually benefit a lot more from more hp than more attack, so it could survive shockwave, lightning bolt, otyugh, etc. I mean, look at anubis, it's 5/8, and this is 7/4 (or 8/4) and anubis is still used more, even though it requires a duo.
I do think this is one of the nymphs where having higher att/def is okay, because the ability isn't that great when compared to anubis or quintessence in-element, or most of the other nymphs. (as opposed to the proposed changes for water/light and especially earth nymphs, which are too much)