Arthur Romeo... like the car? I'm bad at this

The movie “King Arthur” portrays a much more realistic homage to the myth of the king than most other representations, though it’s not without moments of questionable reality. The most obvious instance is how skilled all of Arthur’s knights are as archers, namely Tristan. He’s shown to be able to pick off Merlin’s soldiers with ease, even while shooting into the woods, from hundreds of yards away with no idea of their exact locations. Later, when Arthur and his knights fight the Saxons at the frozen lake, they all have a range two to three times that of the Saxon soldiers, even Guinevere, who prior to that was an unassuming serf. Guinevere does become a total badass later in battle, but until that point there was no reason for her to be this skilled. Furthermore, Tristan was the only knight shown to hold a bow prior and it was established the Saxons were superiorly armed. I also find it odd that the entire lake was frozen over when there was no indication that it was winter outside of a light snowfall the night before. Which just reminded me, if the Roman lord knew it was winter, why were he and his priests so lightly dressed? As for the final battle, I feel that it’s a reach to accept that Merlin’s army pledged support to Arthur based one vague, brief meeting in the forest and his relationship with Guinevere. While Lancelot killing the lead Saxon’s son was cool, I think it’s unlikely that he'd be able to accurately and with force throw his sword 15 yards into a man’s chest while having an arrow in his.