Seeing how the Anime has yet to even showcase even ONE aspect of the so-to-be-believed "fifth generation", I'm beginning to think that the Anime may indeed come to an end by the time Ash presumably completes the BF at Johto.
I also think that Dawn staying on for the next saga (IE, the BF saga) is a terrible mistake, seeing how by the time they even GET to Johto, the main Gen IV games (ie, Diamond, Pearl, and Platinum) will be completely outdated, thus making her purpose (advertizing Generation IV's main games) completely useless. I mean, at least with May, they kept her because Emerald was most recent (although I still don't like the fact that they treated Leaf as if she never existed. I mean, even Brendan and Lucas got more appearances than her, and that's saying a lot, seeing how they only got a few second cameos in movie openings.), plus the fact that her main reign was called "Advanced Generation" instead of something like "Ruby and Sapphire" helps things in her favor. But in this case, it's completely different, as not only is the saga limited to the main series ("Diamond and Pearl"), but Platinum, unlike Emerald, was released before HGSS.
I mean, if the Anime writers or game writers were to make confirmations of a Generation 5, they would have shown us something by now (They already unveiled all three special event/movie Pokemon, and they haven't even shown us a sihlouette of a Generation V pokemon.). I mean, in the First Season, they had Ho-Oh and Togepi in the main anime (as a matter of fact, Ho-Oh was the first Generation II pokemon seen in the anime, which happened in episode 1.), in the movie, we had a Snubble, Marill, and a Donphan. In the second season, we had a Marill, and an Elekid appear. Likewise, in the second movie, we had an Elekid, Lugia, Slowking, Hoot-Hoot, and a Ledyba appearing. In the Johto Saga, we had a Keckleon (which first appeared in the middle of the region), as well as a Blaziken and a Wynaut. In Movie 4, we had a Wailmer, and in Movie 5, other than a Wailmer, we also had Latias and Latios. In Hoenn, we had a Munchlax, and in BF, we had a Weavile, a Mime jr., a Bonsly, a Mantyke, a Buizel, a Chatot, and a Manaphy (both in the anime, and in the movies). Arceus has been revealed for quite a while, and his movie has been out for a month, and yet they still haven't even come close to revealing a next gen pokemon, not even their sihlouette. This, as well as the fact that it's still doing quite poorly on ratings, leads me to think that the anime is coming to an end. Unless we try and do something to save the show, the show will end in a painful way.
EDIT: Even IF there is a Generation V in the works, that does NOT mean the Anime will end up following that route. Take the Mario TV series, for example (and this is a very notable example, as up until Pokemon, the Mario TV series was the longest running TV series related to a Video Game (about four seasons, which are two seasons of "Super Mario Bros. Super Show", one Season of "Adventures of Super Mario Bros 3", and one season of "Super Mario World".).). It got cancelled after Super Mario World, and did that stop the Mario games from continuing even into the states? No, it didn't. I mean, they could have easily halted any shippments of any Mario related games after the TV series ended to the states (as the cartoon, much like Pokemon, was technically created as a way to advertize the games), but they didn't. If they can do it, then so can Pokemon.