While I don't know a huge amount about the technical stuff behind this if the 'dust' transactions are what I think they are then I think they should be kept, my reasoning being that one of Bitcoins main features are that it is easy to divide, if you restrict that then it becomes less useful and convenient. Then again, I could be entirely wrong and this is something completely different to what I'm thinking off, I was thinking that the restrictions were about people sending 0.000005 BTC amongst themselves or something.
dust has nothing to do with restricting decimal usage. you can still use all the decimals if you want. its just, in a sense, limiting your ability to send transactions that will cost the recipient more to send then what you sent them. (read carefully that last part) in fact. dust really has absolutely nothing to do with decimals. its a matter of value.
would you spend 1$, to mail in a coupon, for 1 penny off a online purchase? Sure it makes that thing online 1 penny cheaper but you just lost 1$ doing it! Who would do that? This is what the change prevents.