A lot of the motivation for the 1MB limit was a fear that if it weren't limited we'd have people building gigantic blocks just to clog up the system. If someone with major hashing power started building giant blocks every time he got a block, he could DoS the system just by making the block chain too large for most people to store.
How exactly would this be done? Where are these transactions coming from? Could this "bloating" attack be detected and these blocks rejected?
It would be better to prevent this some other way and remove the limit entirely.
This has already been addressed by Gavins original post. Maximum Block size would for example grow 50% per year to allow for more transactions in each block, per year, while still keeping storage costs relatively low. A totally unrestricted block size has never been spoken about.
be done...