ready for Mil/Aero applications? From a strictly technical standpoint, can you answer "why not?"
CPCI Serial is virtually apples-to-apples with OpenVPX. They have the same 3U and 6U sizes, the serial fabric speeds are the same, and they are both proven in highly ruggedized applications. If CPCI Serial is rugged enough for outer space, its rugged enough for any earthbound project. More vendors are introducing conduction-cooled modules and even versions for Space.
CPCI Serial is also lower cost than OpenVPX and is certainly a lot simpler. No complex "profiles" to mess around with. OpenVPX does have a jump in some of the optical and RF interfaces that are attractive in some applications, but that is still a niche requirement.
Why hasn't CPCI Serial taken off in Mil/Aero applications? It probably more due to marketing perception and logistics than anything else. The main board vendors are all from Europe with smaller players in Asia. (But, many of VPX's largest players are European companies too). The initial focus for CPCI Serial was largely for the Transportation market. Plus, one of the largest players has corporate governance rules about being involved in weapons systems.
What has changed? There is a tipping point in ruggedized versions of CompactPCI Serial and popularity. There seems to enough traction and activity in the architecture to take on new markets. (See the Did You Know? section below for a satellite application note for CPCI Serial for Space). Plus, not all Defense projects have offensive weapons, so there could be multiple large players serving the Defense market. As both OpenVPX and CompactPCI Serial are based on the 3U/6U Eurocard form-factor, a lot of the enclosure/system work can be leveraged across both platforms.
It will be tough to take on the perceptions out there. But, when the Defense market sees there is a "low-cost and easy-to-use OpenVPX" out there, I think it will pique the curiosity of many frustrated engineers looking for another solution.