What's the story behind these profiles? I know that the Rangers of the North first appeared in The Battle of Pelennor Fields supplement, what I don't understand is why they later created Dunedain of the North in The Ruin of Arnor. From the story part they are the same! The could just add the armor option. Am I missing something?! Not to mention Rangers of Arnor and their fluff...

The Dúnedain profile represents the rangers while they were active in the North, mainly while protecting the Shire. The Rangers of the North profile represents them riding to war. I think GW probably couldn’t go back and change the existing RotN profile so had to create a separate new profile without armour.

My guess is eventually they will become a single profile with an option to take armour, spear and a horse.

Back in the days of Legions of Middle-earth, the Dúnedain were also available in the Shire armylist, while Rangers of the North were solely found in the Grey Company one. Of course, they could just have made the armour optional and not allowed it (nor horses) to be added in the Shire list...

Good point Coenus Scaldingus, that would be a good reason to have 2 profiles.

They could do that with Kingdoms of Men book, but they didn't!

What is bothering you about the profiles? As an avid user of both profiles (mostly RotN) I am curious.

What is bothering me the most? I guess, is the fluff.
Dunedain of the North are Rangers of the North. There are no noble houses, men of Arnor, men of the lands about Fornost, etc. They are all the same people! Which point out to one profile with options for armor, spear and horse.
One more thing I would like to mention. Warriors od Arnor became Rangers of the North. They did not coexist in the same time period which is the case with Arnor army lists (those with Arvedui and Malbeth)...
To me it is very strange that GW guys made these "mistakes". It is like they didn't bother with Tolkien lore enough.

I can see where you are coming from. That aside, the Dunedain and RotN were released before the warriors of Arnor. And since there are no time period rules in the SBG the two (warriors and rangers) mix quite well. If it is really bothersome, you could implement time period rules in your play group and knock most of the problem out.