I'm pretty close to what you would consider a modern viking. I mean, no, I'm not big and musclebound and chopping heads off, but i am descended from danes, swedes, norwegians, germans and celts, meaning i am made up of the stock of conquerers who successfully spread their genetic and cultural seed across northern europe. My ancestors made Romans take pause and say perhaps the Danube was far enough to extend the empire. Beyond their martial prowess, they were expert sailors and established trade routes as far as Russia and the middle east. Their cultural contributions have influenced modern day culture and traditions in Europe and beyond. You can thank my ancestors for the most memorable and fun aspects of holidays such as Christmas and Easter--boring Christian holidays spiced up with some pagan flair. With the possible exception of the zulus, the japanese, the apaches and the mongols, my ancestors were the closest thing our species has ever seen to actual Klingons, and that is worth celebrating by keeping the name of the Vikings

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Native americans need to be the ones to debate over and decide when they find native american cultural stereotypes to be either offensive or inspiring--I think it's a case-by-case thing, but I am white and thus have no "skin" in the game and will shut up. I don't get huffy and complain over these changes, I could care less what these teams name themselves, I just think they can come up with something better than guardians or commanders. Those are some of the most uninspired, bland names and sound like generic high school team names. Redskins may have been about as racist as they come, but at least it stuck in the memory and had a pretty iconic, albeit outdated logo.
What I would like to see for amusement's sake would be for these teams to keep the offensive and outdated names, but let's see other teams rename to various offensive slurs. Let's see the North Jersey wiseguys and the mascot is just a fat mobster in a track suit. How about the Kentucky Crackers and their mascot is a redneck? There's a lot more I can think of, but I can't list them here because it will probably get me banned.
I also think that the NFL could be reinvigorated by adding 2 or 3 randomly placed landmines to every game, and by equipping the players with various melee weapons such as bats, blades, maces, etc. This would cause a lot of death, but imagine the ratings. It would mean a very high player turnover, but this is good because it would give more up and coming college players a shot.