Nintendo had no need to go guns out in 2008. No matter your views on the depth, quality and "hardcoreness" of this year's releases, the company (let's not forget that that it what it is) knows what it is doing.

There's nothing wrong with using sales of MKWii and NSMB for example to interest new adopters as they are quality products. The difference with that and the HD consoles is that they do not have the 1st party brand.

I honestly think we will begin seeing a transition back to mainstream gaming for nintendo (they were never core save for a few franchises like FE)

I think they are in phase 2 of 3.

Phase 1 was capture Nintendo gamers and peak the interest of Casuals. Zelda at launch did a good job of this, then Metriod and Mario (also brawl was supposed to be a cmas 08 title) in the First year sealed up all the Nintendo gamers, then phase 2 which were are in. Capture the casuals, it is working imo better than phase 1 did. WiiFit, MKWii, Wiimusic, WiiSports resorts, and other stuff.. Phase 3 will begin next year as they build on what MKWii is starting (tradtional game selling to casuals)

One they have completed there 3 phase plan they will then follow a more traditional pattern to get some HD gamers who see no reason to buy a Wii right now. 3rd partys will have to help in this. I think it will succeed in Japan with what we already have announced, the west is still in question.

You know, Nintendo has more franchises than just Mario.

Those are just the ones I could think of off the top of my head.  Plus this doesn't count games that are already announced or new IPs that we don't know anything about yet.

Harvest Moon is not a Nintendo franchise; it belongs to Marvelous Interactive, and is published in the US by Natsume (and in Europe by Rising Star).

I think Nintendo doesn't need to release a big title right now and they're trying to let 3rd party developers have their chance.

Nintendo is making titles right now. They announce Punch Out! so that is coming soon.

My bad.  I knew Marvelous developed it, but thought it was published by Nintendo.  I could have sworn the N64 version was at least in the US.

Nintendo have held back to an extent, due to demand exeeding the supply, but not to an extent it's seen in the OP.
Also, Nintendo did release one big core game for the christmas, which was Animal Crossing (nearing 10M on DS).

The biggest reason for the delays propably is Wii Motion Plus. After the announcement of WM+, the core propably wants the support to every game (and Nintendo of course wants every game to support it to maximise sales of the peripheral). Animal Crossing was a game that couldn't make much use for WM+, while Wii Music would definately had benefited from it, but it was left without WM+ for two propable reasons: Nintendo wouldn't had anything for E3 and because Wii Music required lots of work to program the instruments for the songs, WM+ would have required basically the whole game being redone (also, Nintendos music team was used heavily in making the game, it would have bottlenecked the whole EAD for their musical team being on remaking Wii Music).
We'll propably see what Nintendo have been up to after WM+ comes out.

not too mention they haven't announced anything just because they knew it would piss off trestes.

^ funny!