Does anyone know for sure that the Fourth Generation won't be in this game? No [save... you know. 8U]. I, too, would enjoy solid proof whether they are not. <3
Of course, it's decently possible, but I simply find it illogical. Diamond/Pearl has been out for almost a year in Japan, so seriously. AND WITH THAT, I would assume Sakurai has adapted himself and SSBB to the newest generation of the Poke'mans, as he has now with the Third Generation.
Of course, I don't know everything, and I could very well be wrong, but still. This is my take on the subject.
And Venus, there is no pattern. SSBM came out decently before [... about a year and a half if I recall correctly] the Third Generation of Poke'mon-- which made it pretty much impossible to put Wailord in. >:
Anyway, Dialga and Palkia would be <3. I can't be bothered to think of the effects of their attacks, mainly Palkia's Spacial Rend.