I think everyone is doing it wrong. Forced HD is just as restrictive and stupid as no HD at all. It should be an option and developers should then make the call themselves about whether or not their game should support it.
But you forget that HD support would make the hardware more expensive, and Nintendo wants to actually profit from their consoles unlike MS and Sony. If they included HD support then they would either have to charge more for their console, or else sell it at a loss. What they are doing by leaving HD out makes perfect sense - especially since most consumers don't even have HD TVs to make use of it just yet. In the end, HD does make a sharper picture, but it has absolutely no impact on playability or fun factor of games.
It is the gimped hardware that is more the problem. By being too different the decision for a third party is either "X360 and PS3" or "just Wii". The Wii is a great option if using the remote makes sense but for a game that uses a "normal" controller the other consoles are more ideal. Make a "traditional" game on the Wii and there is a hardware limit that the other consoles don't have. The Wii isn't better or even equal, it's just different.
Actually, I think the nunchuck arrangement has proven that any traditional sort of game can be done on the Wii. The only real problem is that the motion control is there, and most developers think they must incorporate it somehow, but that isn't the case at all. I remember the DS was like that in it's first year or two on the market. Every developer seemed to think it was necessary to make use of the touch screen, so you even had games like Castlevania requiring the touch screen to draw seals after beating bosses, but it wasn't really necessary, and the developers seemed to have learned from that because now there are lots of DS games which don't rely on the touch screen at all.
The Wii is like this now, and many developers want to tack on motion controls where it isn't necessary and doesn't make any sense, but they don't have to. The Nunchuck and Wii-mote combo have all the analog sticks and buttons necessary for traditional gaming. All they have to do is just ignore the motion aspect. Plus, there's also the Classic Controller too. So the Wii has no real difficulty handling traditional games.
Plus I think the kids console crap is still very much alive. Sh!t like friend codes doesn't help. Neither does promoting grandmothers playing your console. Neither does the lack of HD or the "weaker" hardware. Kid focused products are often dumbed down and the Wii is very blatantly dumbed down. I remember when the N64 had cartridges, many people I knew assumed Nintendo did that because they're easier for kids to understand. Once the idea is in their head people are going to look at any irregular decision and come to the conclusion they want from it. You dumb stuff down and then promote the whole family playing and you're just damning the console to be full of third party kid focused crap. But then how else would they get the non-gamer market? I'll admit I can't think of a solution to that.
I know what you mean, by the "kiddie" crap, but it really makes no sense whatsoever since the Median age for a Wii owner/player is a good deal higher than the Median age of their 360 or PS3 counterparts. The 360 and PS3 are actually the immature consoles, if you think about it.
Nintendo is the kid that gets made fun of a school and shows up the next day wearing a pink shirt and suspenders. It's the bully target that you feel sorry for, but still seems to bring it on themselves. They shouldn't pick on you, but do you have to be such a weenie little dork? Third parties shouldn't jerk Nintendo around but Nintendo shouldn't give them so many excuses to. I'd like to see Nintendo design a console without any blatantly obvious cons or tradeofs or lame excuses that might make a developer question support. They've been shooting themselves in the foot for three consoles now and, surprise, they've had sh!tty third party support all throughout. Despite regaining the top spot with the Wii, Nintendo has still never given themselves a fair playing field. If they ever do I imagine things will improve dramatically, regardless of what market share they have going in.
They've definitely made some mistakes here and there, but they've managed to remain profitable all this time, even though their last two consoles are labeled "failures". Could they have done better? Absolutely, but at least they are still a 1st party unlike Sega, Atari, or 3D0. Heck, they must have learned from some of their mistakes because they are the market leader again. I think the "kiddie console" stigma is beginning to loosen up a bit, because now we're seeing things like No More Heroes and Bully, when stuff like this was unheard of in the GC era.