Although The Wrestling Observer is not a reliable source anymore, I feel excited each time I hear the reports

If Sting comes to WWE, him going against The Undertaker is the only feud I'm interested in watching. And it should stretch for 3 months at least, unlike Taker's current no-rhyme-or-reason feud with Brock Lesnar. Both The Undertaker and Sting are great storytellers, both have a huge presence in the ring, they don't need mouth-pieces or managers, to be a heel or a face, hugging kids or taunting them... they can just be themselves and everyone will buy it.
On the other hand, if he and the negotiators decide to have more than one match, or a full one year contract, its more than likely, almost inevitable, that he will end up in the same ring as John Cena <--- the momentum ruiner, the guy that has had more than enough people "pass the torch" to him already; he will pin and land Sting in the same state as the "Embrace the Hate" Kane or returning Brock Lesnar, because he for some reason has to get involved with every superstar that's rising or returning, 9 out of 10 times beating them clean. While I'm totally okay with Sting getting younger wrestlers over (something he seems to have no problem doing, as witnessed in TNA), John Cena is the only reason I don't want Sting to sign a full time contract.