Indeed, nothing has changed regarding the presets.

I have added this request to the tracker:
Issue 2031 – Allow transfer settings presets to add to the default file masks instead of overriding them completely
You can vote for it there.

Btw, I'm not sure what "original poster 10 years ago" are you referring to.

Is this still the case, that the transfer settings file mask (Options > Preferences > Transfer > Edit > Edit) is global to all sites? I, like the original poster 10 years ago, maintain numerous sites many of which have one or two file types or folders that I don't want synchronized.
Thanks!

Copy. Thanks, Martin.

Unfortunately, it's not possible atm.
You have to copy all masks to the preset.

I have a long list of in the default transfer settings file mask (Options > Preferences > Transfer > Default > Edit > File Mask). For some of my sites, I want to exclude an additional folder (typically one that stores data on the server). Is there a way to add a file mask for a specific site yet still use the default mask, or do I need to create a preset that contains all of the masks that are currently in the default transfer settings?

The former approach (i.e., allowing a mask in addition to the default) is highly preferable, because I have a dozen websites and would prefer to not maintain the shared mask settings (i.e., those in the default) for all sites.

Thanks!