As many others have already said, Nightwave is a great idea and represents how far Warframe has come.
It adds tangible goals for players to complete during their normal gameplay, and each tier feels good, reward and progression wise.
As a veteran, Nightwave gives me a reason to play, and some of the rewards feel great - mainly the cosmetics.
With that, I can understand the frustration of newer players, the removal of niatin alerts alone are devastating, I still remember hunting for those for days to craft several items, I have no idea how I would have done it within nightwave, even if you spend all your creds on niatin, it won't be enough for nothing more than a couple of weapons.
Same goes to catalysts and reactors, those alerts were rarer, but they could still give players at least one per week, and now you actually have to choose between potatoes and niatin? I think this might be asking too much of your players.
This game is already confusing (not to say abusive) to new players, which is a shame, because once you pass that mountain you discover a real gem, but I can see how nightwave's reward structure might be burdening new players to the point it can feel as it's too much.
My suggestion? take the best of both worlds - keep nightwave structure as is (a bit more variation in the cred store would be appreciated next round)
BUT, add back daily niatin and the occasional reactor alert.
I can understand, design wise. why DE would not want to increase the amount of creds they give out substantially,
but adding back some alerts will allow players to smooth out their progression curve (which, let's face is, is alraedy very grindy),
so they will remain active and happy players.