Dynamic Routing over VPC is supported but not in all the cases , there are few design scenarios that you should consider for it. Also if feasible you can route over a Non-VPC link . NSX-Edge to Nexus over a Non-VPC Link ,but you are right edge cluster demand is there in that case.
Support & Downloadsed Topologies for Routing over Virtual Port Channel on Nexus Platforms - Cisco . Just go through the section ->Supported Topologies for Routing in a vPC Environment