Not sure what you mean by "normal", but Saft is a "plugin" of Safari (which does not have a plugin API), so it's not a normal application. But sure there are many things in Saft that can be improved - I have a big TODO list, and you can send your requests to me too.

One thing though, if you think Saft makes your system crash, then it's hard for me to believe it, since Safari+Saft is just a user space application, it can NOT crash MacOSX, unless that there are some things wrong in the system (and Saft just trigger it).