It is completely "possible". For one thing, the event is confirmed to feature only 2018 releases, so Prime 4 is most likely a no-show. I think Bayo 3 is probably a 2019 game as well. And Pokémon will not be there unless it is revealed separately this month; TPC likes to unveil their games themselves.
On the other hand, we are confirmed to get a ton of Smash 5, which will be hype af. Fire Emblem is by all accounts still on track for this year, and that reveal would be super exciting for me. Animal Crossing might appear, which is always popular. And, since Nintendo is actually capable of keeping secrets, who knows what crazy stuff will be revealed completely out of nowhere.
So yes, it could be great. But it could also just be decent. The only thing that is certain is that it will not go exactly like you or I expect. That uncertainty is the magic of E3.