I'm the guy who went over the blockchain stuff in Satoshi's first cut of the bitcoin code. Satoshi didn't have a 1MB limit in it. The limit was originally Hal Finney's idea. Both Satoshi and I objected that it wouldn't scale at 1MB. Hal was concerned about a potential DoS attack though, and after discussion, Satoshi agreed. The 1MB limit was there by the time Bitcoin launched. But all 3 of us agreed that 1MB had to be temporary because it would never scale.
Is there a link to original post where Hal Finney and Satoshi discuss the block size limit and DoS attacks?
The forum didn't exist when that conversation was happening. I've always assumed these discussions were via email or some other medium. There aren't any transcripts that I'm aware of.