Not at all. It is either really efficient, or (more likely) low on charge. Ideally the low side is still cool when it leaves the evaporator.

If the expansion valve is cool, then the compressor is likely working well. However, a pressure test might be in order, since the ex. valve will always be somewhat cool if the pressure is higher than the low side (but possibly not high enough). If the comp is weak, you'll have a cool expansion valve, but a warm low side because it isn't pushing the right pressure through the system, nor keeping suction side to a low level.

If the output air from the vents is cool, don't worry about what the evaporator lines feel like.

Just a little food for thought. It is likely just a low charge.
--
Chris Herbst, near Chicago.