I see no reason to expect more spam just because unlimited rewards aren't potential. It's remotely possible some folks would post more, lower value content. I don't care. That's an insignificant matter compared to rampant profiteering that has utterly broken curation, and is dropping Steem's market cap about 15 places per year. Leaving downvotes unchanged handles spam with facility now, and would continue to.
'Milking' posts is already done, and the additional work making more posts entails reveals good work ethic. These are trifles compared to the existential threat Steem is under presently, and that EIP would worsen.