I see it a little differently... I don't think the split needs to be changed, I think something needs to be done about the bots. I've been meaning to do the math and write up a post about it, but my observation is that bots vote very early. That is, within a couple minutes, a popular author will have dozens of votes already... and sure, those bots are getting smaller rewards because they vote early, but they don't care. More importantly, what also happens is that each one of those bots lowers the rewards for anyone else who follows because the first votes get a higher percentage of the reward.
So if 10 bots have voted at 2 minutes, and you vote at 30 minutes you'll still get a small reward because the 10 people ahead of you got the majority.
I haven't been able to think of a good solution yet really, but I think the key is limiting the bots' influence more than anything.