An application extension programming language (AEPL) has to simple and productive. For its users will likely not care for indepth knowledge of it, will develop simple, small applications and will expect the programming effort to pay quickly. A small, orthogonal set of familiar features will help the programmer users getting started.
The language should not impose heavily on the interpreter or on the application. The resources commanded by the interpreted programs will be ultimately managed by the application, and the application can only manage so much.