Holiday 2015 for Nintendo home console, and they will drop the Wii name. It will be a marginally more powerful console than PS4, it will still have a game pad and it will start at $299.

Buddy, there ain't gonna BE a 9th gen.

When Nintendo starts making PCs

Holiday 2017: Nintendo home console (back to the 5 year cycle, the Wii lost all momentum in the year before the Wii U came out)
Spring 2018: Nintendo handheld
Holiday 2018: Sony home console

I think there will be no Sony handheld and maybe even no MS home console (but they will stay in the gaming business).

What would dropping the "Wii" name and boosting power do?

It would be the Wii U all over again.

Nintendo min. after 5y (2017)
Sony min. after 6y (2019)
MS do SEGA

New Nintendo handheld in early 2017, Nintendo console in late 2017. New Xbox late 2018.

As for Sony, I think there won't be a PS5 and they'll stick to Playstation Now and Playstation TV, assuming all goes as they planed. Though I think they'll release a new Playstation TV in late 2018.

Differentiation for starters, making a break from a name that now means failure, and is forever associated with casual motion controlled gaming. Wii U (a stupid name to begin with) was based on the idea that they could partly cash in on name recognition of a wildly popular product, the only other time Nintnedo have done that in home consoles is NES/SNES. Only they didn't realise that in the later years Wii was actually not very popular at all and it was never paticularly popular with the traditional gamer market base.

A power boost is necessary to 1) make Nintendo versions of multiplats the best version, 2) not be an excuse for 3rd parties to leave Nintendo out in the cold on multiplatform titles, and 3) to pique the interest of the traditional gamer base who has rejected the Wii U precisely because it is underpowered. Like it or not a lot of people on whom the gaming industry depends for ongoing viability actually care about the power of the machine they are buying. It's one of the reasons PS4 is selling so much better than the other 8th gen offerings, even when you remove the price difference from Xb one and PS4.

It is clear that Nintendo 1st party titles only sell to a relatively small player base, so as much as Ninty fans want to believe the home console can survive without 3rd party support (or with 2nd rate versions of multiplatform games) it obviously can't.

nintendo will make another console. what else should they do?

Power won't bring 3rd party's to Nintendo.

Honestly, without some type of "new" thing, Nintendo will never be that successful with their consoles.