Tonight was the first that I had heard about WOTC possibly dropping Greyhawk from the Core Rules. To tell you the truth, I can't think of anything that would make me happier. In my opinion, the Core Rules should be completely generic so as to compel players and DMs to either purchase published material or make up their own. It can only increase business for all publishers as well as increase the customers creativity.
As for WOTC handing the rights over to another publisher, I have mixed feelings about this.
Part of me thinks that they should keep it as they have the most resources to develop it.
Part of me feels that selling the rights to a third publisher who wants to devote their own resources to the setting would also make sense. However, that course of action would only create arguments over who should have control and who should have input into what has become a legendary and living campaign setting.
There's another part of me that believes that WOTC should show loyalty to the RPGA and allow them and encourage them to actually publish their version of the setting. After all, they are the ones who right now are carrying most of the burden of creating new material. I'm sure that the RPGA could use some money to keep the system going.
But I think the idea that is winning me over right now would be to continue what they started with the d20 system. Personally, I'd love to see Greyhawk open-sourced. It would allow not just new people to chart its course, but would also permit the original and current developers to map its past. If the setting was open-sourced, it would even allow competing game systems to support the setting. In my opinion, this would be the best win-win scenario possible.