As a developer, I want Entity IDs to be of type "String" instead of "Long" because numeric IDs cause many problems.
The generation of numeric IDs can only take place through a central point and often requires DB access; Namespaces can only be represented by numbers, whose management is quickly complicated; Merging data from different sources is conflict-prone and requires a complex encapsulation of the data.
Strings, on the other hand, can easily be generated decentrally (e.g., UUIDs), and namespaces can be easily formed using prefixes. In addition, primary keys from any data sources can always be represented as a string (even if only as a hexadecimal representation of the naked bits), while a representation as long is only possible with keys with a maximum of 64 bits.
Implemented and tested for V0.7.