1. I would include other streams in the homepage. Imgflip should be decentralized so that streams get more attention, as well as reducing workload for Imgflip moderators like you.
(speaking of workload, how much do you spend moderating the fun stream?)
2. The homepage algorithm would be reworked so that memes are more customized to the user's interests. The algorithm would be based on templates & stickers used in the meme, what's the meme text and what stream the meme was posted. The current voting impacts would be kept; upvotes would boost the meme, downvotes would hinder it. But I would also add another equation: comments. A meme that is successful in engaging users into commenting would be boosted in Imgflip's algorithm. I would also improve the search system. An improved algorithm would enable better discoverability, user experience. Such algorithm would also open up for a new revenue stream: Sponsored Posts. As the algorithm is tailored to user's interests, Imgflip could set up an advertising system where advertisers can make posts about their products, and in return Imgflip boosts it. The advertisement would appear to "target users"; someone who consumes posts that are similar to their products. For example, gaming companies would want to target the gaming stream and other similar streams.