Limiting to 4 posts a day might help - but it would only likely be taken onboard wholeheartedly by those who have bought into the true spirit of steemit.
For others who only have eyes for the quick buck and be damned, clone accounts would be spawned with gratitude and rapidity.
Steem is a focal point of human nature. We can peer into it and see the best of times and the worst of times just swirling round and round.
In a room with no rules the words optimisation and exploitation bounce back and forth off the walls. Which word you see and which word you miss depends on which door you came in through.