No.

I think the GameCube is the main cause of Nintendo's current 'image'. The lunchbox-look and the purple color combined with bright large buttons on the controller probably are to blame. They also had the worst timing in trying to do new stuff with Mario and Zelda, instantly propelling the kiddy image further (the water-gun in Mario Sunshine, Wind Waker's cell-shaded approach). During this gen I feel GameCube's image-failures were only amplified by the Wii's lack of power and third party support, as being some kind of 'proof' for Nintendo's focus on kids.

Before the GameCube, Nintendo consoles were different. SEGA tried to paint the NES and later SNES off as 'uncool' in their advertisements, but I don't remember there being a public consensus on Nintendo's 'kiddy-ness' like today though. The N64 was definitely not viewed as a kid's console, despite being aimed at all ages.

Note, I only remember history from the late SNES generation upwards as I was born in '88 and only six years older than you, so I'm not old enough to know the complete picture.

The difference between "core" and casual IMO is how based on how well informed said "gamer" is not necessarily what games they play IMO. I agree with you that people who only play COD and/or sports games are casuals.

The easiest way to tell is to look at their video game collection. If they only have stuff that's been heavily advertised on TV for long periods (COD, Sports titles, GTA, some nintendo titles, etc), they're probably casual. If they have something like "Shin Megami Tensei: Devil Summoner" in there or any RPG in general (this is due to the time investment usually required to play these along with various nuances i.e they are not just pick up and play), they're probably core gamers.

I don't know that there is a misconception as to the age of Nintendo gamers in general. I have seen some people in their teens/early 20's who are fans of an XBox or Playstation say that Nintendo games are for kids, but I don't think that is the view of the general population. It's also definitely not true, as the demographic is pretty similar for all systems. Nintendo tends to have more kids playing, and more older people, while Xbox peaks with above mentioned teens and college kids and PS3 has a mean age slightly older than the 360 but a similar demographic. Wii's mean age is the oldest, but it's just a broader selling system to all ages.

My perception among my friends was that kids pick up Nintendo games, old core gamers like me pick up Nintendo games that they've been playing since the 80's, girls like a good round of mario, families have them for the whole group to enjoy. PS360 seemed to be more narrowed to an activity that just the guys did, usually the 16-26 demographic, with some older like me.

Yeah I know alot of people that just play FIFA and cod, there as casual as you like.

That would be my view on core/casual as well.

I'm 33 going on 34 this year and I play mostly Nintendo games.

LOL, I am 28m and i don't see me playing any other console in the near future.

you got to check the NINTENDO fans on youtube, 90% of them are dads. Just to let you know. All channels i am subscribed about Nintendo fans commenting, those guys are above 30.

There is such a thing as being young at heart, but I think you need to make a distinction between fans and loyalists. A gamer can be a fan of games on the platform, and yet play on multiple platforms. While a loyalist plays on that platform exclusively. The reality is that Nintendo doesn't have a lot of those, and fewer still hardcore loyalists. The first group is most assuredly casual in nature. While the latter is probably on the older side. They started with Nintendo a long time ago, and they have become just plain habituated to the brand.

In the case of the last group you could say there is a misconception, but not much of one. They may be old, but they are actually playing games geared towards a younger audience, or at least not geared to anyone specifically. I think most of the misconceptions about games come expressly out of that group. They still think in terms of the rivalry between Nintendo and Sega. They very often automatically assume that Mature gaming is about blood and gore. Sex and mindless violence. You tell them Nintendo should get more mature games, and their brains go right there.

Yes some people are still litigating a argument today that they made when they were eight or nine years old, and they just never stopped to reconsider that belief. So a lot of older gamers do in fact come across as if they are eight or nine years old, because they are making arguments from that point of view. That isn't fair to say however that it is fair to generalize a whole fan base no matter where they fall on the spectrum. It is however understandable that it happens since those that haven't moved a inch since they were eight or nine years old. Are usually the loudest voices in the chorus.

Your stating opinion as if it is fact.  I would say Nintendo probably has some of the strongest, largest groups of brand loyalists - I am not one, as you describe it, but I think they are a very large group, as such groups go.  I also think it's downright disrespectful to say they have the mindset of an 8 year old.  And if you feel that Nintendo needs more mature games, and that such games are not sex and gore, what do you think their games need?