The instructions we give instances when importing are basically "go drag and drop your SQL dump into /file/". These instructions have some stuff going for them:

• They work.
• They accommodate gigantic files gracefully.

However, they have some downsides:

• They're error prone (users try to use the upload control, which doesn't work).
• The fact that policies are set correctly isn't clear.
• They feel very, uh, "boutique".

It would be better to create a little "Files" area on instances, where you go to Instances → My Company Instance → Upload Files or similar and get a nice upload area that looks and feels more purpose-built.

Fixing T5187 may also be desirable here, although it probably isn't strictly necessary.