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human
CMV: Aang is to blame for the failure of the Day of Black Son invasion

So if you have ever seen the show Avatar the Last Airbender you should know the main character is Aang a person who has control over the element of air and is the Avatar a human who has the ability to learn and master a four of the elements which are Water,Earth,Fire,and Air. One of the Avatars' ace in the holes is the ability called the Avatar State where Aang basically synchronizes with all the past Avatars to ever exist and then has near God-like control over the elements becoming damn-near unstoppable. Now the Day of Black Sun was a small invasion of the bad guy Fire Nation with the hopes of ending the war then and there since the Black Sun represents an eclipse a time where all fire-benders lose the ability to fire bend. Long story short the invasion fails and it's because of Aang and his inability to truly want to win by killing.Aang could have teamed up with all the waterbenders and flooded the entire island drowning all fire nation soldiers and the Fire Lord (main bad guy) Aangs reluctance to ever consider killing since he was a monk put his entire group in danger and resulted in a massive failure. 
TLDR: Aang had the power to win the war if he would have just drowned the island with the help of all the water benders but choosing not to put others in danger and in real life would have gotten some killed
CMV.
gpt
For one you're overestimating the power of waterbenders. What you're describing is a feat that we've nevery seen a waterbenders capable of pulling off. Furthermore, if memory serves, there were not that many waterbenders. Members of the Water Tribe, yes, but not all of them are capable of  waterbending.

An Avatar State Avatar might have had the raw power to do that, but Aang literally did not have the Avatar State.

Finally, if memory serves, the coast was on a steep hill, not a flat sursurface and had plenty of raised walls. It would take a ton of force and a suit ton of water to even pull off what you're suggesting.