Bug resolution (communication), AAI mechanisms (user registration to use API), UI development takes intimates knowledge of RPID at this point (still obscure), "test-bed" classification (adoption), intellectual issues (mapping, granularity, interoperability, merging data), still trying to tell our story to new potential adopters (education).
Non-Issues - Operations on test-bed scale, porting service from AWS to baremetal to Openstack was easy, migration of DTR data simple (even with a format change).
Unknown - If existing software libraries (Azure or AWS) will easily plug-and-play with ERPID services. If not, additional development effort will be necessary. Can "Types" be used as level of indirection? Will Types work as we envision them.