it needs to change to mbits of something smaller because its a bit of a mess
and new users will struggle to equate value of a payment like 0.0035 to buy a coffee that costs $2.50 in fiat
a whole bitcoin will soon be out of reach for many people and the decimal point placement
is a bit tricky if we dont start using mbits or ubits etc
The problem of decimals is fixed pretty well via punctuation
that for some reason isn't standard (IE: 0.013,275,0 BTC is easier to make sense of than 0.0132750 BTC at a glance). On the other hand, I feel that we should switch to mBTC simply because many people don't initially understand the concept of divisibility. While it can be argued any new user should understand how the currency works, nobody in the general public really gives that much of a hoot and you know it

a $5 sandwich costs 0.00703125 BTC at current gox rates

(not including the tx fee )
its going to get worse as coins get more valuable and we have to go further back
past the decimal point to pay for small items
its only a matter of time before coins will have to be sold in fractions as well because buying
a whole coin when the price reaches $10,000 will be too expenisve for the average user