They very concept of a coin is not consistent with something that costs hundreds or thousands of dollars. People already work their way around this. They talk about protecting or spending their "bitcoins" even when talking about less than 1BTC.
Using the term bitcoin in the plural form should become rare. Just like you don't go to the ATM to withdraw some monies, or get a drink of waters from a water fountain.
Making this change just requires a modest conscious effort to go in the direction with the least linguistic resistance. A true semantic stock split will catch on and take over on it's own. Just like tipping a boulder off the edge of a steep slope.
A milliBTC is going to become a common unit, since it is going to be more or less scaled to similar amounts of USD or EUR. If you want to want to use a word for a milliBTC that does not have a current definition, more power to you.