My first guess was details due to the planchet flaw. It wouldn't be a big deal on older coins like colonials that have planchet flaws all the time. But I have a feeling the TPG's would be hard on newer series like Buffaloes that don't normally have them.
I know I asked for opinions, and as such they can be anything, but... on what planet is this a VG reverse? Full Horn = VF this coin has 3/4 horn, a full tail and most other detail as well as full rims... where do you see VG?
You have to send those in under the error category. A normal submission risks a details grade for those
As the code 93 states - "depends on severity". In other words if the planchet flaw is bad enough the coin won't be cleanly graded; if it isn't too bad it will be. Your coin has 2 areas affected by the planchet flaw - one that extends from the rim across the leg and into the lower central fields, the other on the belly of the Buffalo. In my opinion that makes it severe enough to qualify the coin for code 93, thus my comment. Would a TPG agree ? They might, they might not. But you were asking for "our" opinions so I gave you mine.