I am thinking about activating the SharePoint Server Publishing Infrastructure for our site collection, but worry what it could possibly cause.
What, if any issues could this cause to content already on the site?
As a short answer There is no issue on site content,
But before you decide to activate the
SharePoint Server Publishing feature or
Community Site feature for a team site you should first be aware of the following:
let’s summarize the above points:
For more details check my article at MISSING SAVE SITE AS TEMPLATE IN SHAREPOINT
One thing it will definetley cause is that you won't be able to save any sites as templates - though as far as I know, you can still save individual Lists and Libraries as templates.