I mean, if they want to totally kill it and "win the show" they should drop several big title announcements in my opinion. I agree with Oedo that those titles should all be there, but then the narrative will still be "Nintendo shows not much news, Switch line up remains sparse, yeah we knew about all of these already" etc.
So here's my completely unreasonable line-up I would want to title drop if I was Nintendo's PR and had somehow gotten all these very unlikely projects in near-complete stages without anyone noticing until now:
Bayonetta 3, just to really rub it in once more. Show off those perfect 10 scores for the previous one. Oh yeah and it comes with free copies of the first two games too, so no "I didn't get a Wii U so I can't be up to date on the story" excuses either.
Metroid. A big one. Dual release with a side-scroller on 3DS set after Fusion. Flashy, no Federation storyline, no voice acting. Call it Metroid Andromeda just to stir up ****. It could be sidescrolling, something different, or Prime 4 but...
New Retro Studios project. Preferably a unique, new IP with Splatoon-esque immediate broad appeal. If they're doing Prime 4, then it should just be them dropping 2 games in 2018 like it ain't nothing.
Beyond Good & Evil 2. Platform exclusive. And we're not Kickstarting it it *side-eye Shenmue which inevitably got hype during the Sony conference* oh and also Jade will be in Smash 5 which we're teasing this show but won't be out for another year or two.
Of course none of these will happen and I'm being a totally entitled fanboy now. But it'd be great marketing and it's just fun to daydream haha.