2018.

What do you think of the fact that GC had over 200 packaged games in 2003 while Wii U has only ~10 packaged games released in US so far this year including such hits as Transformers Rise of the Dark Spark, Hello Kitty Cruisers and Big Game Hunter?

Never

I'll never say that it won't pass up, but things are pretty grim. However, it really depends on how successful the amiibo toys end up being as a marketing tool. If those really take off, I wouldn't be surprised to see a notable increase in Wii U sales. It could reach 25 million if amiibo is as popular as Skylanders/Disney Infinity is and is well supported in terms of software.

Never.

I don't see it happening, it's possible but extremely unlikely. If I had to guess I'd say never.

I think 2016.

2015 is looking as though it's going to be a strong year: X, Splatoon, Zelda, Yoshi, SMTxFE (plus unannounced)
2016 will probably be the peak year (think we'll see 'proper' 3D Mario, Metroid, Starfox)
2017 will be slowing down, then successor announced at e3
2018 last real year of sales

2017 or never, once it's done it's dash it will drop off very quickly.

Fortunes have improved to some extent but it needs to push up to and around the 100 000/week mark and stay there to have any chance. Smash Bros and next year's line up should help but it may not be enough. I think if Nintendo is clever they can pitch the Wii U as the 'must have' second console, a lower price would be a significant part of that strategy.

It might happen in 2016, but I think 2017 is more likely at this point!

The only thing that Wii U might have in its favor, and I say might because it may not happen, however I believe the Wii U will have a longer life then the Gamecube and thus have a longer time to sell units. To really answer this question we need to wait until after Smash and Amiibo come.