Thick bindings aren't refactored code, they're a different interface. "Thin binding" means a shallow interface, possibly even autogenerated from C header files. "Thick binding" is usually abstracted, creating proper Ada data types (including the normal restrictions on them), different functions and procedures (perhaps bundling common sets of activities that would be a series of calls in the base C library), adding Ada tasks if its sensible to the system (which it may be, like wrapping around a network library, you can have the network connection handled in its own task).