OpenBabel is a great project, the main reason why I did not take it and add the features I needed is that I am not so familiar with C, so learning it AND getting into other people's code would have been a lot of work.
pikashu
supports many formats that are not supported by OpenBabel. Also, the aim of this program is to be able to perform some transformations on the system in a simple way, which OpenBabel still lacks at the moment.
If I need it or if I am in really good mood I will add the support for new file formats and new transformations. However if you need something peculiar you will probably get it faster if you program it yourself. Check the information for developers.