The '14 is soon (?) to be adopted here in NJ, and I admit being not complete on reading the changes. There is a 6 month period after adoption to the effective date. I've read into the end of Chapter 2 & picked thru others.
The 590.4(j) change you mention has some interesting commentary to the 'why'; and should result in some interesting 'compliance' attempts at some sites.
I see the reasoning, but reading the commentary in the changes book I have, the lack of GF protection on the feeder/branch circuit is mentioned. Would not requiring that the feeder/branch circuit have GF protection??
Think about the 'costs' to attempt support that may be compliant in the eyes of the AHJ, vs. the cost of a GF device. IMHO, the GF solution would be a better requirement.
FWIW, some of the ECs have been protecting the 'temps' with GF for years. Yes, it can be a PITA if the feeder GF trips, but if it helps being safer, why not?
Or, am/did I miss something along the way??