Answers:
How does it prove they are running out of ideas? The names. 'Nuff said. Pokemon Black and White 2. As if those names were bad enough. By 'They' I refer to Game Freak and Nintendo.
One; How do you know? They are entering the world of 3D, so wouldn't it be XYZ, as if in, Height, Depth and Width? That's a big bit of speculation as well. Too be honest, I wouldn't be suprised if it was something strange though, like Pokemon A, or Orange or Amber or Grey or... well, you get the point.
Two; Yes I know. Pokemon Y is better than Pokemon X. Proven by the awesome bird legendary. If you look carefully, the stag (it's a stag) does have an X in it's eyes. Look carefully at the trailer.
Three; I don't think so. The bird legendary (or Wyvern), seems to represent Evil, and the Deer Good. There is no link whatsoever currently to the DNA and Science theme, more Fantasy than ever really.
Four; MOOFASA!