The low side should definitely be cool to the touch when the system is operating properly. I doubt there's a restriction in the system since the pressures aren't way out of whack, just not getting quite to where you'd want them to be. I'd expect abnormally low pressure on the low side if say the orifice tube was clogged. I would second the compressor, it could just be worn out if it's the original and has seen a lot of use.
I'm unsure of the design that GM uses on these compressors, but I know on older Honda's when the compressor gets worn it can trigger a thermal switch on the compressor and "disengage" it until it cools. I've also replaced many compressors due to age (typically above 120-150k miles on the original) that display similar conditions to what you described.
