The conclusion that "swing" states would lose importance is not consistent with the objective of the National Popular Vote concept.  The swing states are important because they have a high population now and would continue to have high population with a purely popular vote election.  In fact, given the current slight advantage the electoral college gives to low population states, which would be lost under the purely popular vote method, swing states would become relatively more important.  I find the drive to tinker with the system that has served us well for over 200 years based on discontent over Trump to be unfortunate.  Naturally, the democrats support this move because the small population western states tend to vote Republican and they have a slightly higher weight in the electoral college.