@aqwxsz The idea is under consideration, which actually means nothing :) But the Core team is aware of the problem we have, and there's some work being done to (probably) make it happen in the future, first of all - check the Taxonomy Roadmap. Additionally, making slugs non-unique is a large task which will break backwards compatibility, which isn't "WordPress-way of doing things". Permalinks, as they are currently implemented, rely on slugs, which isn't good but that's what we have to deal with.
