username0136 while the Flarum team reads every message under the "Feedback" tag and tries to give feedback/consideration where needed, we expect most of the suggestions will be picked up by community extension developers.
So "putting burden on the developer team" isn't a reason to not make a feature suggestion (or bring it back up with new ideas). All suggestions are welcome and might give ideas to new extension developers discovering the platform.
Also while increasing the number of extensions can have an effect on performance, it's not a reason to stop creating new extensions. Using extensions is exactly the reason why Flarum is fast, because you can include only what you need.
At this time there is still no plan to implement this feature into core itself but this would be a wonderful community extension to have.