For me the term "Compact System Camera" is accurate and also sounds almost lyrical. I'm not sure whether the acronym CSC will become widespread though.
If I were to invent an acronym which sounds better and is easier off the tongue I'd go for DSC (Digital System Camera). It eschews the word "compact" but in 50 years time who's going to notice?
On second thoughts in a few years our attachment to the word "digital" will be thought quaint. There's no need to describe these cameras in terms which differentiate them from SLRs or DSLRs so how about
That differentiates them from compacts and superzooms and, within a few years when flappy mirrors, as opposed to pellicles, have bitten the dust the term "system camera" says all that needs to be said. To be fair, DSLRs are also "system cameras" but the term isn't commonly used for DSLR marketing purposes so far as I'm aware. Is it possible that such a term could become associated in the public's eye with the new breed of cameras?
P.S. For me the word "system" means a lot. With compacts and superzooms you tend to get what it says on the tin and any accessories are usually camera specific and have to be discarded when you upgrade the camera even if you stick with the same manufacturer. With system cameras you at least get a strong likelihood that lenses etc. can be used on your next body so long as it belongs to the same system.
P.P.S. Did you notice how natural the use of "system camera" was in the paragraph above?