I don't think we'll see that many in January, but when you add in E3, I'd be surprised to see less than 15 new games announced next year. Of course, a number of these will be smaller titles.
You need to convince early adopters that the system isn't going to dry up after 6 months, you need to show them stuff that is coming later, even over a year away. Doesn't have to be gameplay trailer, but a tease, a title card, a cg trailer, anything is enough.
- Show monster hunter double cross switch HD and then tease monster hunter 5.
- Show smash bros and then tease more smash dlc
- Show xenoblade X port and tease xenoblade 3
(not those things exactly, of course, but ) Just, let the audience know the system has a good launch and a good future.
Then at E3, show more detailed trailers for fall lineup and even more teases of what's to come that weren't ready in january.
I don't think 'saving stuff for E3' is a good strategy in this case. Yes it makes E3 a 'bummer' when you know most of the stuff already, but coming out of the gate as strong as possible trumps a good E3. if this were launching AFTER E3, then sure, make E3 for megatons, but it's not, it's launching before. "E3" needs to be in january, plain and simple.