not recommend for class action
1. different courts have different opinion regarding this (yes, it is true that many court have favorable ruling for immigration)
2. to be class action lawsuit, all cases should be very similar, and this is hard, for example, "how long is unreasonable delay " ? There is NO clearly definition for this
3. The only exception is for "naturalization with interview done over 120 days" -- they can all refer to 1447(b)