The newer all alloy rear freewheel seems to have slightly more friction when it is new. I think this is due to the extra sealing it has to keep out bad weather. This is very slight and does not have any effect when pedalling. I got one of these as a replacement and now after a few months use it has freed up a lot.
When folded, if the rack is fitted, the bike can only be pushed forward (as backwards the freewheel engages, and turns the crank … solidly). Forwards the cranks can turn, but only a bit, before the freewheel kicks in an does its job.