I wish the author would finish, or at least make SOME progress in their other current series first, but that's just me.. Edit; Oh, this is completed, never mind then! Though it doesn't excuse the state of that other one..
If you are proficient in english it's very easy to skim over mistakes and correct them in your head unknowingly while reading, even after reading it (x) amount of times.
We all make mistakes and learn from them, but yes I do agree.
Also if you see mistakes it's better to point them out specifically (that makes it easier to fix)