One big usability improvement for features is the addition of cargo-add which can be help in editing features with its table of whats activated.
The next is making it more explicit which optional dependencies are optional features but this requires crates to update to rust 1.60 and make some changes.
Something we are discussing is changing `defaut-features = false` and re-adding what you want to opting out of each default feature. With the current behavior it can be a pain to re-enable what you want and crates can't move existing behavior to a feature without a breaking change.