I have no problem using the mBTC and µBTC, but as I have seen more and more having problem with these SI prefixes, it makes me start feeling the suggestion of using "bits" does make sense.
If 5,700,000,000 people have no problems with mBTC and uBTC and 300,000,000 Americain can learn it why change it?
I am not saying we should stop using the metric units, but we can use both of two systems.
It is like we are also using kilograms and pounds for weight in different part of the world.