I think a nice feature is to make ghci like bash in this 
sense: 
pressing <TAB> complete the identifier at cursor like 
bash complete path and filename, showing a list of 
matching identifier when there are two or more or 
overloaded identifier into loaded modules, like:
*MyModule> ta<TAB>
Prelude.tail MyModule.tail
*MyModule> ta

Bye,
 VampWire
monstered@mail.com