This sounds familiar...
Nicholaz; this sounds like a problem several of us have experienced with Spacemaker fridges.
Under normal conditions, the high pressure side, and the low pressure side of the system will equalize, in 5 or so minutes after the compressor stops. The compressor is not designed to start up against a lot of pressure in the high side. That is why the guardette will trip if there is a power-blink. The system tries to re-start before the pressures are equalized.
If the capillary tube is restricted, it may begin to take longer and longer for the pressure to equalize; and also this will reduce the refrigerant flow while it's running, causing the system to lose capacity. That could explain both the long run-times and the hard starting.
Just to be sure; check that the thermostat isn't short-cycling the compressor. Be sure it is not cycling off, and then trying to cycle back on too soon.
Hope this gives you some good pointers.
Sincerely,
David