It's probably not bad. Black might play ...Ne7, and then later Ne7-c8-d6, blockading the d5 pawn. This pawn obstructs the light square bishop somewhat. Black will probably be able to play around the advanced pawn.
well the entire point of the example was about how black is "executing" the free central d-pawn rather than "retaining" it. So if white can keep this d-pawn without any serious penalties... then I think I'm missing something about the example.
So I'm confused about a position of a game in "My System" by Nimzowitsch. The game is supposed to be an example of dealing with the free central pawn on d4 (white's move 5). Rather than "restraining" the d pawn, he is directly attacking it with 9... e5!. My question is, why isn't the move 10. d5 a good response? This seems to save the d pawn. Instead, the game ends 10. Qe2 O-O 11. dxe5 Bg4:
If you have the book, this example is in chapter 1, at the end of section 6.