If there is a significant difference between the drag with the pads in (after pressing and releasing the brake) and with the pads out, suspect old tired piston seals in the calipers.
A gently push should eaily turn the wheel, but dont' expect it to keep spinning more than half a turn or so, if that. You should be able to turn the wheel with you palm flat on the tire without pressing down more than a tiny bit.
There is always some noise from the pads brushing the rotors, they never move very far away, but it should only be a hissing noise that doesn't add any drag to speak of.
If stepping on the brake and then releasing it makes the wheel very hard to turn, one or more pistons is sticking in the bore.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!