I don't expect the new 3D Mario on launch month because there's very little time to promote the game as big as 3D Mario. It's probably an E3 showcase then will be available near or during holidays.
As for the launch titles, I expect the following 1st party games:
- Zelda BotW
- Splatoon enhanced
- Mario Kart 8 enhanced
- A totally new, unannounced game
We'll probably see some additional 2-3 games within 3 months. Maybe more ports, or maybe new games from the January announcement. I expect to see Pikmin 4 in January announcement, but will be released a month or two after launch to promote the game some more. Then at E3, they'll probably do the bigger reveals, and maybe more Wii U ports. Some of the games I expect to see at E3:
- The new 3D Mario
- Smash Bros 4 port
- Retro Studios' new IP
- Pokemon game from Game Freak
- A new HAL game
- New Monolithsoft game
- Exclusive 3rd party games from Japanese partners like Bamco, Capcom, KT, Platinum, SEGA/Atlus
Some of which will slowly trickle until the end of next year, and some will probably get to 2018-2019 like your usual HD games nowadays.