Maybe it's just me, but I would be leery of leaving a well-established program to join a brand-new program that won't have any of the kinks worked out yet. Especially given that when you transfer programs, even from one well-established program to another, there are discontinuities and inconsistencies between the sequencing of rotations and requirements from program to program. This could be quite a gamble in terms of your overall quality of your training experience.
For me personally, I did not want to be a program's "guinea pig" during residency. I did interview at program that was only in its 2nd year of existence, at a very prestigious institution and with some potentially great opportunities. But ultimately I decided to rank several well-established programs higher, because for me, the stress of residency seemed like enough to handle, without the additional chaos of the inevitable growing pains of a new program.