If you’re ever looking for context behind why we change something, I would recommend checking out the patch notes for more context as we try to include explanations for why we make changes there. In TF’s case:
With the lack of Mythics in the new item system we wanted to take advantage of the opportunity to broaden TF’s viable builds for those looking to take advantage of the newfound freedom with their itemization options. Ultimately, this should help players that are picking TF and suddenly find themselves against a tanky comp (or in an AP heavy comp) where AD TF is more appealing. These changes will mainly benefit those looking to build AD TF, but we also have a few smaller changes that will be beneficial regardless of the build. While we still expect AP to be his primary build and will support him with that in mind, but now he should have a viable alternative build.
He landed overtuned which is why we’re nerfing him next patch, but hindsight is 20/20 and experimenting with fun ideas carries a degree of risk. But without the risk associated with the test and learn process league would just get stale imo