We have a Whirlpool fridge with french doors, similar to this model that is around 2 years old.
We have both the fridge and freezer parts sets as cold as they will get. This is -5F for the freezer and 33F for the fridge. The fridge is staying about this cold, but the freezer is only getting down to around 24-26F, and it seems like it is warmer because some ice cream we keep in this freezer always seems very soft when we pull it out.
This unit also seems to be inordinately slow at making ice. It has the ice container in the door, and even re-enabled the "fast ice" feature every 24 hours it isn't keeping the ice bay full even with only moderate ice usage. (I would estimate usage is no more than a quart by volume, including gaps between the cubes, while the bay itself holds a bit more than a gallon.) I'm not sure what the long-term effect of perpetually commanding fast ice is, or if this can be a problem. It's not fast enough for us even on the "fast" setting so I'm a bit perplexed by this setting.
There does not seem to be any blockage in air flow, but it seems like the unit runs a lot - although it is pretty quite and unless you stand up close to it or actually open the freezer drawer you might not know it. It was repaired for the opposite problem about 9 months ago (not cooling in the fridge part) and they replaced - I want to say they said it was an invertor.
Update: When "fast ice" is turned off the freezer temp does drop slightly - about 4-5 degrees, so it's around 20F, which is still 25 degrees above what it's set for. I suspect that fast ice is really just trying to direct more cold to the ice maker in the top of the fridge, but with temperatures only 5-10 degrees of melting it's no wonder ice takes so long to make.