Introducing a secondary leaderboard for the main levels that takes into account the highest score achieved by a player without using any abilities.
With a decently upgraded research tree, it's relatively easy to get into the top 1% of the regular leaderboard in most levels without using abilities, and I like the simplicity of relying just on towers, miners, and modifiers to maximize score. Adding a secondary leaderboard for levels played without using abilities would introduce a new challenge for players who have already tried to climb the regular leaderboard, and although the strategy isn't that much different, it would be interesting to see how much of a difference abilities make in the top scores for each level.
Of course, the regular seasonal leaderboard would be the definitive leaderboard and this one would just be for variety's sake.