I'm new to the community and I just noticed the same as you; Most of trends are run by whales which makes minnows like me hard to compete.
Creating three different categories would help with it. However, the incentive to vote a minnow is not as good as voting a dolphin or a whale because the expected value of the curation won't be as good. So just adding three categories won't end up the problem. There is something that needs to be done to increase the incentives to upvote minnows and dolphins.