I think your idea is very good and would be a nice measure to make steemit visibly more diverse to newcomers and might actually enlarge the society of the most popular by a bit.
But we also have to keep something else in mind. The trending page itself is not the most important issue, it's just a way to make the issue obvious (and I'm not even sure if I want to call this issue a problem really though it might be considered as such). The issue is that the biggest rewards are generally had by the same limited pool of accounts. And anybody that's surprised by something like that should really reevaluate their views on how a free market works.
What we see on the Steem blockchain is what we see in the real world as well - the parties and agents that have access to the most money, resources and/or power end up leveraging that and gaining even more money, resources and/or power. I understand that many people here are firm believers in the free market as a driving force of progress and I do agree to a great but often not full extent, but this shouldn't stop us from noticing its shortcomings when we spot them. The underlying process that makes the trending and hot pages so homogeneous and repeatable and the exact market forces that allow the 1% to keep expanding their lead and reach inside free economies.
Now spotting the issue might not be so hard (although some might find my reasoning controversial, especially here), but the big questions is would we want to do something about it if we could and what. I'm personally not even sure the issue I'm talking about should be classified as a problem and not an expected state of affairs in a free system. Or we might want to try to offset the trend somehow. One thing that we can do and that many people are already doing, including people that can get into the trending page is support newcomers and smaller authors. Changing the trending page the way you are suggesting would certainly tug things in that direction as well. But we should be realistic in our expectations and realize that this is not just the trending and hot pages, but a much deeper underlying issue regardless of our attitude towards it and our evaluation.