Well, i think the fued of 'new school vs old school' is a nice, fresh direction for TNA to attempt, plus makes alot of sense since most fans have been annoyed about the over pushing of ex-WWE talent at the expense of the TNA originals, even though Joe is the champion he is not nearly as over as he was without the belt, or even prior to his fued with Angle and that was two years ago.....having said that i feel it could work successfully with Sting as a heel or a face for two reasons...
1) with sting as a heel, I feel Joe needs to beat sting at BFG...otherwise the bad guy would win and while furthering the angle, that makes Joe look even more like a chump not a champ...especially after needing help from Jarrett to retain the last two months. But then if Joe does beat sting at BFG, what then for the angle...do they just shake hands and move on, seems unlikley so what then...maybe sting wins and defends againt Styles, eventually dropping the belt, possibly but what about Joe, lost in the shuffle, fueding with Angle or Booker...whatever happens with him, it doesnt look particularly good. Maybe Joe loses at BFG then wins back the title down the line, shaking hands with sting then and proving himself to the icon...but still not the best outcome for BFG on the night, i really feel Joe needs to win, much like cena beat HHH in 2006 in a similar situation with the crowd cheering the veteran, while booing the young babyface, but the wwe put cena over, for the long term future.
2) Sting as a babyface could work better cos Joe would not look bad in losing, if he were working as a heel, since the match would be structured to build the crowd against Joe and in favour of sting. Then sting could hold the title a while before dropping it back to Joe, then turning Joe face again with a handshake to symbolise a 'passing of the torch' like undertaker vs Brock Lesnar, a few years ago.
Overall the angle is most intriguing since, as said before, there is no clear cut heel or face...both sides have legitimate opionions and all are beloved performers but, i agree it makes most sense for the young guys to be the faces and the old guys the heels cos the logical end to the fued should see the tna originals going over clean, proving themselves and becoming established stars...while sting, angle and booker, etc, are already stars, so they hardly need the push or the 'rub'. Plus as also said before, sting may not be a true heel in the old school sense of the world, but angle and booker surely are, so in order for sides to develope maybe sting will remain nuetral and alone, while the heels form an alliance against tna...then after the angle is over sting will have plenty of heels to work with on his way out, putting over guys like Robert Roode, James Storm as well as Joe and Styles which seems better for TNA long term than having sting beat these guys.IMO