Wait, what exactly is it missing?
-Games with dedicated servers as opposed to peer-to-peer (P2P) connections, otherwise you're literally paying for nothing when it comes to actual online play. As it is right now, paying Nintendo for online play isn't actually improving it, because the connection can only be as stable as the host player's connection under P2P, Nintendo can do very little otherwise. P2P is one of the most simple and basic forms of telecommunications and isn't really designed for the kind of information that needs to be rapidly sent in sync between multiple players in a larger multiplayer game like Splatoon. Without dedicated servers,
you are paying for nothing when it comes to playing your favourite games online which you previously could play for free. Paying for dedicated servers is why people are OK with paying for subscriptions like PS Plus or even paying for subscriptions for specific online games like Final Fantasy XIV.
-Many core titles do not and likely will not ever support cloud saves due to Nintendo's lack of foresight, which somewhat defeats the purpose of having it for many people. Instead of, for example, tying save data for online rankings in Splatoon to a cloud via your Nintendo Account, Nintendo tied them to your local save data, leaving us in the situation we are in now where they are afraid of save scumming (i.e. people backing up their save data when they reach Rank A, get demoted to Rank B, but then download their backed up save to get back to Rank A). Things like that should have been saved to a cloud to begin with rather than locally if they were so afraid of this. The two things that make this bizarre is that they announced the online service well in advance of major titles like Splatoon (meaning they had time to implement such measures), and we also know they DEFINITELY have the means to do it as it's how they handle their mobile games like FE Heroes (for example, the data related to the units I have and the Orbs I have isn't saved locally on my device, or at the very least, only part of it is. The rest of it is on a cloud server and the data is unusable without being connected online and linked to my Nintendo Account, which makes cheating a lot harder as I can't just crack open my save file and edit values to give myself a free +10 Legendary Marth with his optimal kit, or give myself 9,999 Orbs for free).
-Can't really personally vouch for this, but I've heard a lot of reports of the NES emulation being subpar, even causing a visual glitch that requires restarting your Switch to fix. And overall, these NES games feel like the only substantial piece of content you pay for, which isn't saying much. While I'm positive they will bring other titles to the service like SNES and N64, they need to have this thing be updated regularly to even remotely justify paying for a year of the subscription. It can't be just a couple of small NES games every two months or something.
-I know they said they're doing special offers, but there needs to be, on occasion, discounted first-party titles to purchase, because if it's just a few slightly discounted indie games, nobody is gonna care. Indie games are already pretty cheap and affordable, so most people aren't waiting for them to go on sale. And if they are, they're waiting for them to be sold much cheaper on another platform because Nintendo eShop sales are rarely very good.