Well I for one like to vote on most of the post that are made by some of the people I follow. If there was a 48 hour delay, it would mean that it would be best not to post more than once every two days if you wanted to get votes from your loyal followers, or people who continually vote on your posts.
I see the problem with multiple accounts, but there should be some other way around the problem, if there is a problem. I don't know who uses those. Maybe the people who post plagiarized stuff all the time? Hard to spot, so I don't know how common it is.
Admittedly, it is my least favorite change as well and one I would love there to be another solution to. I am open to any and all suggestions that would accomplish that same goal without making that change. I personally haven't figure out what that might be just yet though...
My solution would be to differentiate between more and less effort. I wrote a post about it yesterday. I think it would help at least. Because then the other accounts would need to either write more as well or it would take them longer to accomplish a level that mattered. If your interested to know more you can check it out, but basically the idea would be to separate tweet like posts and blog posts. Reward them differently based on length of post (doesn't guarantee quality, but is a start I guess).