Well... they are good sugestions, but they would also cost half of Nintendo's fortune with little garantee for returns.
I think in special the part where they say to please the third parties cant happen even if nintendo wanted. They are blocked in terms of engine on the Wii U. For any 3rd party pleasing to happen, they would need to either convince Epic to make the new unreal engine compatible with the Wii U, or they would have outright buy Epic to make sure this happens. Again its alot of spending for what is questionable returns.
As for buying SEGA, i think that is the best thing they can do. SEGA has a very diverse portfolio that in the right hands could be a very good value for Nintendo. For example they would have a 3D fighter on Virtua Fighter, a 2D fighter on Guilty gear, they would have a high profile adventure game on Shenmue and Yakuza, they would get Sonic and Sonic racing and could take turns with Mario to avoid IP fatigue. They would have MMO's and hunting games in the form of Phantasy Star, great JRPG on persona and SMT aswell as having a brother strategy rpg series to fire emblem on shining force. SEGA is the answer to the IP fatigue Nintendo is going through.
They would have to sell the pachinko business though... and while at it hire Yuji Naka and prope to work on some of those SEGA games.