First, if you do this, you will over-write user customizations.
Second, you should not substitute any template not created by Word as the Normal template. Only Word can create a fully-functional Normal template.
Here is my webpage on Templates in Microsoft Word.
You can distribute Workgroup Templates and Global Templates. You can use custom [Quick] Style Sets and Themes.
You can have a different template be the template used as a default for new documents without it being the Normal template.
Here is my Add-In which could be adapted to your situation. It explains how to do it.