A Main Event Mafia vs. Aces & Eights feud sounds like a bit much, since (almost) all of TNA/Impact Wrestling are fighting the biker gang. But, nevertheless, I REALLY enjoyed the original incarnation of the MEM faction (Angle/Sting/Nash/Steiner/Booker/Sharmell) until it got watered down after Sting left the group.
As far as new members go in this brand new incarnation, I really do hope they focus on the "Main Event" aspect of the "Main Event Mafia" name, meaning I hope they don't add guys like Magnus or Eric Young - who have never won the World Championship. Personally, I think it would make sense for the new Main Event Mafia to be this:
Sting, Kurt Angle, Jeff Hardy, Samoa Joe and Rampage Jackson (former UFC Light Heavyweight Champion).
Hulk Hogan is obviously a candidate for the group, but him being the TNA "General Manager" may stop him from actually being a member of the group; and since he's the biggest name, he would likely have to be the leader. But, as we know, Sting is being set up as the group's leader.
(If Brooke Hogan turns heel and joins back with "husband" Bully Ray as part of Aces & Eights, Brooke could somehoe become the new General Manager of TNA/Impact Wrestling, which would lead Hogan to join the Main Event Mafia! Wait and see...)
Bobby Roode is a good candidate, but likely he's remaining heel and focusing on the BFG series.
Another strong and possible member of the brand new Main Event Mafia is the fan-favorite heel and former TNA Champion, Austin Aries. This would bring a whole new level of interest to the group. It's no secret that Aries is LOVED by the crowd - whether he's a face or heel - and now that he is on his own since Bobby Roode is in the BFG series (as mentioned), his whole style could suit very well into the MEM. But Aries taking orders from Sting - let alone anyone - seems unbecoming of his character and attitude. Plus, Aries hasn't really had any trouble with the Aces & Eights recently, like before when he was a babyface Champion of TNA. It's likely, though, he could be asked, rejects the offer, Aces & Eights do him wrong, and ends up joining the MEM with Sting. Who know? My belief is that Aries will remain solo for now.
As for the aforementioned Rampage Jackson, he attacked the Mafia at the end of iMPACT, which means he will figure into the Aces and Eights vs. TNA storyline. Although he may not be around much, having a celebrity status like his may help get more attention to the stable. Rampage in a suit? Perhaps. But his teased tension with Angle may leave Jackson out of the equasion.
Another great-yet-unlikely candidate may be Rob Van Dam. The former WWE, TNA & ECW Champion is currently "in talks" with a top wrestling organization. Whether it's TNA or WWE remains to be seen. RVD is still listed on the Impact Wrestling roster on the website. This may be an indication that he is in talks for a return. RVD in a suit??? That's new...
Abyss may be likely since he is a former NWA: TNA Champion, but the storyline with Joseph Park (Abyss) should be seperate from the stable's return.
AJ Styles is a lone wolf, so count him out...
With this brand new Main Event Mafia forming as "Sting's new Family" let's just hope that the group is a just a small, core group of Main Event TNA Stars, instead of a large faction like Aces & Eights, where wrestlers get lost in the shuffle. If done right, a great Faction vs. Faction storyline, with MEM defending TNA, could turn out to be an eye-opener.
Just my opinion...