I am told USPSA will definitely bid. As of last month, they had not determined the venue for sure.
As to who will bid against them, well, that's unsure until the General Assembly in October.
The Americans carry some weight in the GA that might counter the standard - "it's gotta be in the cheapest place on earth" selection process. The South Americans will support them, as will us. The Europeans will support them if there's no European bidding against. If there is, it will split the vote. Then there's Asia...which is very unpredictable.
For History's sake:
2008: Bali was uncontested - I assumed because any who thought about bidding knew they'd loose to Bali.
2005: Ecuador beat Canada and Denmark. Denmark split the vote from Europe for Canada and two regions who promised to support Canada changed their mind at the last minute. There was a ridiculous debate on how much food you could get for $20.

2002: South Africa was uncontested, I believe - everyone felt that if they still wanted it after loosing in the previous WS vote, they were entitled.
1999: Cebu in the Philippines beat South Africa for the bid.