I've met a few people in Japan of Korean ancestry and they have all mentioned they have a very hard time fitting in and meet a lot of discrimination still everyday. I was always reluctant to dig deeper because you can definitely feel that it's a still a very open wound and something they're still actively dealing with every day.
Some similar anecdotes, while working in a Japanese office there is one co-worker whose great-grandfather was Italian. I haven't seen any actual discrimination against him, but some people are definitely happy to let you know that he is not full Japanese, so I'm certain he's ran across some for his ancestry.
I have the same problems as well with the OS X client. It definitely has issues handling external drives. It somehow doesn't display my exclusions of files on external drives anymore, but somehow is still following them.
I'm really happy with their service (had it for ~2 years now), but would love to have a tool similar to how you describe with reduced bugginess and more tweaking ability.
To follow up on this, it actually turns out the configuration for backblaze on OS X is in XML and tweakable. It can be found in /Library/Backblaze.bzpkg/bzdata/bzinfo.xml
Some similar anecdotes, while working in a Japanese office there is one co-worker whose great-grandfather was Italian. I haven't seen any actual discrimination against him, but some people are definitely happy to let you know that he is not full Japanese, so I'm certain he's ran across some for his ancestry.