In addition to Classic Cliches # 1, 1a, 2, 3, 3a, 6, 6a, 6b, 7 & 9 in Braveheart:
Edward I was a hard man, quite capable of having those he considered rebels executed with deliberate cruelty. On the other hand, he did much to improve England's laws and government, and was a loving husband. There is no evidence he threw his son's boyfriend out a window, although it might have saved time if he had. See below.
As a soldier, Edward was generally a skilled tactician, with a high regard for the value of infantry. His actual tactic against Wallace (after an unsuccessful cavalry charge, launched contrary to his wishes by a sub-commander, was recalled) consisted of keeping his troops out of melee, bombarding the Scots with arrows until holes began to open in their formation, and only then sending in the heavy cavalry. Worked like a charm.
Edward's son, later Edward II, may or not have been a homosexual. His marriage produced several children, but he certainly had a number of male favorites who exercised excessive influence on him. The most famous, Piers Gaveston, was evidently not fatally thrown out a window by Edward I, since he survived into the next reign. He was ultimately executed by disgruntled barons. Edward II was a large, vigorous man, who more closely resembled Mel Gibson than the wimp that played Edward in the movie.
The wife of Edward II was about eight at the time of the events depicted in Braveheart, and living in France, which would have limited her opportunities for romantic entanglements with William Wallace. She would eventually prove to be adulterous and murderous, and was eventually removed from public life by her son.
William Wallace was not a Romantic Highlander, but came from and operated around Glasgow. As the son of a knight, he was probably rather higher up the social food chain than depicted in the movie.
There is surprisingly little evidence that even Romantic Highlanders were wearing kilts as early as William Wallace’s lifetime.
He was apparently betrayed to English, but there is no evidence that Robert the Bruce was involved in any way.
The battle of Stirling Bridge was so named because there was a bridge involved that played a critical role in the outcome of the battle.
And why is it that the only major actor in the movie that's actually Celtic is playing the King of England?