Declaring Rule Inputs in child interface

Yes it is a best practice to declare the rule inputs. There are many reasons to that.
It will make easier to maintain
Defining rule input allows you to test the user interface.
Interface can be reused in many places and it will be easy for someone other than the developer who developed the interface to use it.
If we do not define rule inputs the context of the interface limits to the parent interface most of the time as this will have a tight coupling due to the way we set and use variables in child and parent interfaces.

So define your rule inputs that is a best practice.

Regards
Suresh

Yes it is a best practice to declare the rule inputs. There are many reasons to that.
It will make easier to maintain
Defining rule input allows you to test the user interface.
Interface can be reused in many places and it will be easy for someone other than the developer who developed the interface to use it.
If we do not define rule inputs the context of the interface limits to the parent interface most of the time as this will have a tight coupling due to the way we set and use variables in child and parent interfaces.

So define your rule inputs that is a best practice.

Regards
Suresh