As far as features go number one would be the ability to specify a default generated lisp file if, for example, the specified compiler is not available or compilation fails (which given that most people don't have many headers available on Windows system could be quite useful).
I don't understand, what do you accomplish this way ?
well, currently to grovel the constants on win32 for sockets you will need to have at least 3 header files available. (include "winsock2.h") (include "WTYPES.h") (include "ws2tcpip.h")
I wouldn't expect a reasonable socket library for CL to require you to have a C compiler and the appropriate header files downloaded from MS (IIRC the full download is 100MB or so, or a while trying to find the correct header files) in order to be compiled and loaded.
Granted this problem is mainly a windows one but I think that's a platform that should be targeted.
Cheers, Sean.