The problem with the EU version of Mando society is that it's utterly unworkable. You can't have a whole civilization of mercenary warriors always out looking to prove themselves in battle. For one thing, they'd starve.
Basically it was a highly romanticised and fetishised take on ancient Sparta, with some Celtish sensibilities thrown in...with jetpacks.
Karen traviss had mandos as a group of warriors, but they weren't obsessed with fighting. Many of them were farmers when they weren't fighting, it was actually stated in both RC and especially Legacy of the Force that, while they're always ready to take someone's credits, at home they're very family oriented, and farming is a big thing for many of the families. Boba Fett was actually surprised by that in LotF. He couldn't get as many mandos as he wanted for a mission, because it was harvest season and many were busy on their farms.
Basically, Mandos weren't klingons. Everyone of them, from about the age of seven, were trained to fight, but the whole group wasn't fighting simultaneously, and many didn't spend the majority of their time as mercenaries. Generally speaking, the group was basically only very loosely organized, with little government, because they didn't need it. But, there was still a huge group that had homes, farmed, ran businesses, and did things other people do, they just did it while also having the ability to kick most people's butts.
They grouped together if they were threatened, but they still ended up with usually having a consistent population at home doing normal people things, and by the time Boba Fett became mandalore (after NJO) he started bring the clans together and they basically had a planet of several million warrior mandalorians who were doing things normal for a planet population. Of course, there were a lot of mandalorians who were just mercenaries with no ties or who spent most of their time doing more stereotypical mando things, but there were a lot who were a mix, or who just stayed at home unless they were needed.
^Isn't most of what Traviss wrote about the Mandos based after the events of Jedi, if not further into the future and after the events of New Jedi Order. If, so, you're looking at thirty, possibly even sixty years into the future from the events of Clone Wars. So I don't see why both the events depicted in both can not be possible, the pacifism was a "social experiment" that didn't work out. Upto sixty years is a very long time, hell, thirty years is a long time. American society hasn't remained static in that time period, so why should it remain static for a fictional construct like the Mando's.
On a side note, I really liked Traviss's depiction of them in Legacy of the Force, but I also liked them in Clone Wars because of the tragedy that went with them. It takes a lot of balls to go from a war mongering mercenary society to that of pacifism.
Her Republic commando books started right after the battle of genosis and ended a few months after ROTS. They are completely at odds with TCW, and they are far superior to what that show did. Her LotF books were set about 20 years after NJO., or about 60 years after ROTS.
The only episode I may watch with the New Mandalorians is the one where (and I learned this when I was looking up the New Mandalorians) 
Seriously, Satine getting impaled on a lightsaber by Darth Maul makes me completely forgive the show for bringing him back from the dead, and Satine's death is something I've wanted to see since I learned about what TCW did to the mandalorians. It doesn't fix the mandalorians, but its a nice consolation prize for fans of the real Mandalorians 
