I liked her a lot before but I love her now that her W's mana cost has been normalised. She reminds me a lot of Lulu in that she can adjust her playstyle to how the lane is going, she can be played aggressive but she also does a pretty decent job of playing defensive/passive if the needs be. Q is a bit tricky to hit consistently but I think it's fair given how potent it can be and her E feels quite effective, combined with her W it makes dueling her carry very tricky indeed. Her ult needs a bit of work though, the hit detection seems a bit off with it and I've noticed that sometimes the knock up effect will occur a bit late which can be damning in the wrong situation.
I think I can see the cooldown on her W being raised, it feels very spammable and effective now that you won't go oom by casting it once. Once you get a chalice you can pretty much spam it relentlessly.
I'll definitely be picking up her bundle as long as the skin isn't as ugly as sin.
Her abilities don't frequently hit perfect storm level enough to be a damage focused AP mid nor does she have the most reliable utility.
For anyone curious her perfect storm damage is an R/Q simultanious combo that using the disruption from your ultimate and reading the opponents lets you hit half their team with a single Q (either initial or post effect) just after the ultimate washes over them. Giving a lot of CC and disruption and a really decent amount of damage.
Thing is she can still do that without having the farm of an AP mid and her skills lend much better to assisting people. On the flip side Nami is a support you can afford to build some AP on instead of just aura-stacking. She's really fragile and her abilities do nothing in keeping her alive, but her range is so far she doesn't benefit from building tanky.
You can look at items like the Crucible (heavy mana issues, good support active), Morellonomicon (ultimate will cause 50% healing on their entire team), and whatever nonsense Kage's Last Breath is called now (gold income + AP + minor support active). Ontop of the standard Sightstone/Shurelya's Reverie, have top lane/jungle build Aegis/Bulwark.