This movie was entertaining and exceeded expectations. I love history and am a history degree holder with an emphasis and ancient Indo European culture. I'm not here to tear into this movie as a I felt it was just fine, but rather try to deflect some "junk" history that some people seem to throw into the mixed reviews. Please, if you're going to try to add your own mish-mash of history, at least make sure it's correct.
That's right, I'm talking about you "Russ-was-here". Firstly, your review is off base on many levels, I'll try to answer some of those in a light hearted manner...
The fact that you consider Braveheart to be a "factual" representation of history is laughable, by this alone we can't take you seriously in your review of this movie. William Wallace wasn't running around the battlefield in a kilt, hate to break it to you.
You noted the wide variety of accents here. Is this shocking to you that actors from around the world took part in a movie, and that they all had different accents? The Pict language has been dead for quite some time, while there are rumors that the last confirmed speaker of Pict died in the 1950s, are we to expect the actors in this movie all speak ancient dialects of dead languages? get real (yes, that applies to Latin as well).
Perhaps your biggest mistake in assuming history of this movie is your statement: "Then comes the fight scenes and complete absence of interesting Roman tactics, when attacked and flanked on a long narrow path they simply form a 1 man thick shield wall and wait..." If you had actually studied Roman history (which I'm certain at this juncture you have not even cracked open a Tacitus or Pliny or Martial or any other Roman historian) then you would know the Battle of Teutoberg Wald quite well. In fact the battle that takes place in this movie is a near depiction of what the Germans did to the Romans when they destroyed 3 Roman legions while walking through the Black Forest. Ah yes, some of us actually DO study history. The Romans had no choice but to march nearly single file through a road, when they realized they were flanked on both sides (the line was 14 miles long, thus the battle took place over a 14 mile stretch) the Romans had no choice but to form up as best they could in the road. This proved devastating as it forced Romans to fight hand to hand combat against German soldiers who were more skilled in the area of hand to hand combat.
You mention that the Picts were known for their chariot warfare. Celts (Picts were a Celtic people) were well known for chariot warfare, as were many peoples in the Roman world, as you can see in this movie (especially the battle scene) using chariots would be quite a stupid move as they were in dense forest (use your brain, boy). As we can see with the final battle between Boudicca and Rome, using chariots was not always advantageous. In fact Boudicca sealed her army's fate by following an infantry charge with chariots (effectively crushing her infantry between Roman shields and Iceni chariots).
You also mention they fought naked. Indeed, many Indo Europeans fought in the buff, but that doesn't mean they all walked around in the buff all the time. They were dressed like Vikings you say? You have an odd preconceived notion of what the Vikings dressed like, personally I saw no Pict wearing chainmail (something Normans and Vikings were well known for). Furthermore it's a myth to believe that all Celts, Germans or any other Indo Europeans always fought naked. Many barbarian tribes were incredibly well equipped by 117AD as armor proved to be more and more of a necessity. We also see that Germanic and Celtic armor had a direct influence on Roman armor (Romans borrowed their helmet style from the Gauls for example). As for the movie? It's setting is in the winter, it would make no sense for Picts to be in the buff all the time. This is common sense.
Is this overkill? Yup. But I find your post to be (how did you put it?) completely devoid of historical facts. Does this movie have clichés of the time? Yup. Is the acting Oscar worthy? Probably not. Should we sit here and cry about it? nope. Just enjoy the movie. Nobody here is claiming this is a spitting image of 117AD in the northern UK (shocking, I know), but your post is ill informed and misleading.
Anyways, this is an entertaining movie and you certainly get the feel for the day. Engaging and exciting, certainly worth a view.