Upsides: New characters, increased control over when we get any given piece of candy, able to rack up NW standing in a wider range of places. Plus new shinies.
Downsides: Having to choose between the assorted items that one can get for wolf cred, with the process being potentially slower to catch them all. Assuming you want all of them, anyway.
So now there's an opportunity cost on getting things that used to be alert rewards. But there's also new additional things to be gotten along the way, including some things that were once plat-only, like slots.
Some people seem not super keen on having to do co-op things, which is fine. I mean, I know some people who play WF and am in a small clan, so I can get those, but I can see some people not liking that it's mandatory if you want the standing. Provided it's not necessary to do those to get all of the shiny things, I'm okay with the difference between doing those and not doing those meaning getting the top tier NW reward a few days later.
Stuff like the ayatan dealie is not so much a problem, I think. I had no non-starred ayatans when that first came up, and three days later I had done it. I run syndicate missions with big loot radar and check all the closets anyway in my quest for syndicate gift cards, so I find ayatans at an acceptable rate. The arbitration and sortie rewards also pay out in those on occasion, so getting them is manageable.
It's new players that are more a concern with this kind of thing, I think. Like, I have enough nitain. I have loads of nitain. Sure, once you clear rank 30 with Nora, it's 15 wolf cred per rank (thus far, anyway), and that's worth 5 nitain, but- actually, okay, that's pretty fast for nitain. Reactors, catalysts and auras are still concerns, though. Like, you're going to want a lot of those. They still come up from gifts of the Lotus (we miss you, Space Mom), invasions and sortie rewards, but they're pretty rare from sorties and invasions that pay out reactors and catalysts are decidedly uncommon.
Also when is Hildryn's alt-hat coming up in there? I want that hat. It looks sweet.
I'm going to call Nightwave a net positive change, with the caveat that DE should be real careful around anything that might discourage new players. Maybe hide aura mods in a few other places or something.