Update: I have been corrected internally. Some other customer did request this feature and it was added last year. Hence, I am told, it is possible to do this - I am working on testing it, I will get back shortly.
==> Feature request is for Aerospike Client where if replication factor is 128 then there can be an option (maybe in QueryPolicy) to fetch data from one node instead of distributing it across all nodes (assuming latency difference for smaller namespaces in both approaches are insignificant).