Why would Storm do that? He's injured which is why his match against Ray didn't last long. Secondly, they spent 4 months building a BFG series angle and dedicated a PPV towards it...Why would they ruin it in 2 weeks? They have never done it in the past, so why would they now?
There actually is precedent to taking months of buildup and taking a big, steamy dump on it. Last year at this time, Kurt Angle had run through most of the top 10 list. Don't delude yourself into thinking that list was created to give "fresh feuds" each month. It was created for Kurt's storyline and his valiant babyface quest to win matches the right way and earn back his top spot in TNA. For months, he did just that. Most of his PPV matches over a 5 month period made his opponents look great but he kept coming out on top. The logical conclusion to this story was the feel good moment of Angle recapturing the gold, but that's not what we got, is it?
As people are alluding to, we got a swervy swerve. Not only that, Angle had the added stipulation of having to retire had he lost before capturing the gold (not that this stipulation was even remotely followed afterwords but that's another story). So rather than give the fans what they want at the biggest show of the year, the swerve was pulled and Angle (seemingly) was forced to retire. Instead, there were plenty of disappointed fans who witnessed the birth or Immortal.
This is the only BFG that the current regime has ran and it ended in a swerve that pissed off plenty of fans. You say that TNA has never screwed up a fairly obvious feel good moment but clearly they have. We're also talking about the feel good moment culminating at BFG so the fear of this being screwed up is justified by the fact that the last BFG (and only one done by this regime) ended that way.
Also, why would James Storm screw over Bobby Roode? Jealousy? Disappointment in himself? The realization that he never uses his catchphrase properly and looks even more like an uneducated redneck as a result? There's plenty of reason to believe Storm might screw his partner over, but the reason that some fans believe it will happen is the booking. Again, rather than keeping it simple and giving the fans the feel-good moment, TNA has been known on MANY occasions to overbook things to the point where the results are almost meaningless. Skeptical fans see this as another opportunity to do that. And while defenders may say "well it's fine because Roode isn't ready" or whatever other excuse there is, the bottom line is that Roode has to win at BFG and it has to be a clean win. It's not even about Roode, really. It's about showing the fans that TNA is willing to get fully behind one of their own guys and give him a fair chance to shine.
I want to believe that the right thing will be done in this case. I really do. However, I can understand the skepticism some show in this regard. TNA has pulled the tablecloth out from under everything before, and have broken the plates on top in the process. This is their chance at redemption and I think I speak for everyone when I say that I hope they don't screw it up.