To be honest, I think at the very worst it'll release during the holiday season of 2014.
Though, I'm really curious to know how far in development they are right now. Would anyone be able to estimate that? I imagine they make the stages first, then put in characters then make the items. and since they're showing items they might be pretty far along and near the end. I'm fairly certain development of a game is a lot more complicated than that, so I'm probably wrong in assuming this is the order in which it happens, or even if it follows such an order at all. If someone knows more about game development, I'd be interested in learning about how games like this are actually made.
This is interesting. We know that back in early June the game was complete enough for Sakurai to be confident enough to do a live match without fear of the game crashing or something seriously bad happening, he showed that very long direct of gameplay footage, and he mentioned that he plays four player matches every day during his lunch break. That leads me to conclude that the base engine, while perhaps always open to some tweaks, is fully functional and hahs been for probably half a year now.
In terms of the art assets, which are another huge part of game development, we've seen they are taking a lot of assets directly from other games for stages which will save a lot of time there. Characters all seem to be freshly modeled and animated, and between having to make everything high quality HD for the Wii U, scale it down for 3DS, and then make sure it is going to work well with the 3D on the 3DS, that's a lot of work.
Content in general is tricky to gauge because we don't know how much is actually going to be in the game, but it's probably pretty safe to assume that a lot more is in the game internally than we've been shown on the site. Implementing all the characters and stages is the vast majority of the work required on this front without the presence of a SSE style mode, and we've already seen what's probably a good third of the stuff on that front directly with everything we've seen appearing to be fully complete. How much more could remain unfinished really?
In terms of development time, we know it started roughly when Kid Icarus: Uprising released which was in early 2012. If it comes out in the first half of 2014, that's a two year development cycle which is fully reasonable especially with the massive team they have working on it and the fact that the project is being headed by a big workaholic.
The real verdict is that we can't know for sure where things stand, but it's reasonable to guess this game is pretty deep into development. A release in the first half of 2014 is entirely plausible; I kinda suspect they've been aiming for that all along and just announced the vague 2014 to give themselves a chance to delay it without having to announce a delay if they ran into problems.
In terms of the marketing thing, as a last aside, there's no way the game could be actually finished in the first half of the year and then they sit on it for half a year to sell it during the holidays. That would be business insanity; waiting half a year to begin collecting profits on an investment (and large scale game development is one big investment) is throwing away tons of money, far moreso than the honestly marginal boost to sales a holiday release would net over a release during the spring. This is doubly true when you consider that this is a Nintendo game, and those are well known in the industry for having incredible legs. That means that even if they do release it early, it's not like it's going to have stopped selilng by the holiday; they'll just build the sales with time like they do with every game. In other words, if it does come out around the holiday, you can be pretty sure it's because that's how long it actually took to make the game, not because they had a finished product they sat on for half a year.
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