Diablo closing does not necessarily mean the end of DH riding at Mountain Creek. This was posted on VitalMTB:
UPDATE: We've received word that there will still be a bike park at Mountain Creek in 2012, but likely under a new name.
"The park is built but will need to be re-vamped. There will be a very passionate and dedicated group of people making it happen. The past is now the past and we have a very bright future on the horizon. The park is only going to get better, hard work and love for the sport will GET IT DONE!"
The take away message is that the name will likely change.