I have a Navara on an 05 plate which was one of the first in the country when it was released. They are not all bad and there are a lot of them out there!!
Done 70K now, it had a new clutch, under warranty as they had an issue with the clutch plate being too lightweight under heavy REVERSING. It really trashes it apparently, so they fitted a heavy duty one which has been fine. I dont do huge amounts of off road but we do have a damn heavy horsebox which was the cause of the reversing problem. I also have a Pathfinder now and that has been fine as well.
The vehicle is good in general, but as you say the dealer network is clearly not customer orientated. Nissan UK send out info on the clutch etc, but the dealership deny it for some reason until you present them with the stuff from Nissan UK.
The problem everyone has with a working vehicle is that when it doesn't it costs you more than just the time it takes to get it repaired!!
There is another recall on at the moment for the Navara, for the alloy wheels. They have had issues with wheels cracking, and in extreme cases shearing/snapping off. This apparently may only occur when severe off road towing has taken place. The recall requires you to take the vehicle to have the alloys inspected, if there are anysigns of cracking they should replace immediately, in my case there were none, but they will replace the alloys in due course anyway. This is on a 6 year old Navara! So there are some good coverage but it is almost always only the bad points that ever come up.
Mine has had the clutch done (warranty) the 4wd warning light come on, which involved sensors on the gearbox (warranty) and the prop shaft UJ's were squeaking badly so I had them replaced. Other than that, its been superb to drive.