As long as it coexist along the other models I don't see where is the problem. The more models, the more variety. You don't have to have the latest model of the console, neither your old model will disintegrate when the new model comes out.
The best of having different models is that you can choose the one that best fits your preferences. Since when the variety has become a problem?
And even if some people dislike it, old people and people with vision issues has also the right of playing games. I think it is a good motivation for those people to get a DS.
And sereph, I can understand that you are angry at nintendo because of his politics but, saying that things doesn't make them true. I am along Pheonix Gamma. DS is filled of shit, true, but it has it's own exclusive jewels. Probably DS is the console with the best exclusive titles. Filled with rpgs (if you love rpgs, there is no possible way you can't aggree with this) of an average and above quality and with innovative titles that in other consoles would be a buig risk, so you will never see. Also it's the console with a strong retro taste. Probably among wii the only one with 2D sidescrollers, shoot'em ups, beat'em ups, arcade, graphic adventures, dungeon crawlers and other forgotten genres.
I'm sorry, but I am tired of watching people throwing bullshit to ds when it's probably the only console that has variety, quantity, quality, innovation and it's for everybody: it has great games of every genre, has enough quantity to never stop playing, it has great quality games for the specs of the console: just watch suikoden as an example, not talking about gameplay quality, games are innovative, much more since developmente costs are lower, so risks are lower too. Just look at scribblenauts, and it's for everybody, you can find games for 3 y/o kids and for 70 y/o grandpas. But also for every people of 16-36 y/o.
I think DS should be respected since it did what other consoles didn't: revive old genres and reach to everybody. Even yourself, that hates it, said that there are some titles you might like. This console is impressionant, even if you dislike the behaviour of nintendo.