Pugsley- you are -in my book -right on target.
Having built/trimmed -etc many models -this one was a classic example of a model which easily went into high speed stall.
I sent it to a friend - (ex TOC winner) who lives at sea level - he said the same thing about it .
Now in all fairness - if you really square it away - (trim it )and accept it is this kind of a bird - you can do some very snappy stuff and flail it like a cat's tail.
Just recognize the characteristics -and use em to advantage - don't try to change it -