What we must know is that Kakashi didn't really enter this fight with the intent to kill his student. He only wanted to bring him back to reason which was not the case for Sasuke.
Yeah he couldn't dodge these arrows, but at that time he couldn't know that their speed was so fast(and it was even 2arrows, so it's not that easy to avoid). It took him by surprise. But Kakashi is not the type of ninja to do the same mistake twice. He is smart and will be more prepared for it. If he can't dodge it, he can use clone for example, which is fighting style.
Also, full Susanoo or not, his weakness is the same. You can attack from underground. So Gaara could possibly do the same he did against Madara if there is sand under him. Kakashi with his doton jutsu can also catch Sasuke from underground.
BTW, launching an arrow with Susanoo is faster than Amaterasu, because for Amaterasu you need few seconds to concentrate and launch the jutsu and the oponent could remark it. An example that illustrates it perfectly is that, Bee managed to attack Itachi with his blade even before he launched Amaterasu. Take a look here:
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In the opposite, arrows can be use in an instant. So using arrows is much faster than Amaterasu.
I don't see Sasuke handling these 2elites ninja. I will say Gaara and Kakashi win - mid-difficulty.