Following on from the _autoload.bru suggestion, it would be good to have a default.bru, which could sit in C:\Program Files\Bulk Rename Utility.
The idea behind it would be similar to how the Normal.dotm file is used in Microsoft Word. For example, there are certain conditions in Filters (12) that I always want set, I always use " - " as the separator in Append Folder Name (9) when prefixing folder names, I always use "%Y-%m-%d %H.%M.%S - " in Auto Date (8) when prefixing date/time, and so on.
It wouldn't stop you from changing the settings, and it wouldn't stop you from opening other .bru files that would change the settings - but it could be set to load whenever the program is launched, whether from the start menu or right-clicking on a folder or file. So, there would be an option in Preferences - Load default.bru on program launch - Yes/No. I would also add a 'Default' button by Preview, Reset and Revert, so that you can reset to the default settings (with Reset remaining as a complete reset).