i've already discussed this, and for some reason, people get vicious when someone considers that it may be the last generation. when i posted my own topic on this theory, people were quite rude. well...
i'm with you on this bippa. i believe that it is the last generation. as much as we've heard it, G/S/C were supposed to be the last generations. consider the legendaries then: you had the sea bird, the rainbow bird, the three elementary dogs. you'd think this would be the last generation, but it did so well, GameFreak thought "what the hey, let's continue it". so they went from colors (r/b/y), to metals (g/s/c), to stones (r/s/e), and now, the most exuberant rocks of all, diamonds and pearls. in terms of pokemon, they went from the ancestral pokemon (mew), to the holders of all time, all space, and death (Diaruga, Parukia, and the other guy XD). in addition, they add in the creator pokemon, who i call Zuesmon lol, therefore ending the mystery of what is pokemon.
other factors also come in play: the newest generations making-up for evolutions and such and has somewhat made the variation of moves and types on an equal level. you must also consider the fact that D/P were just made for collecting every pokemon possible, as if all there's left to do is use them to their greatest abilities.
with all of this, i have come to beleive that this may be the last generation. the only factor that says otherwise is how D/P is just ONE series of pokemon games on the NDS, which means that emulation is not possible. also, the upcoming Wii game is just one as well. you'd think that GF would take the advantage of making the most money they can while they can, so it only makes sense that they'd continue making games for both the DS and the Wii.
