Modern impact if they changed the legend rule

WotC has indicated that they are dissatisfied with the current legend rule:

https://magic.wizards.com/en/news/feature/sneak-into-design-with-teenage-mutant-ninja-turtles (near the bottom)

I was doing a thought experiment on what would change in the format if they just completely dropped the legend rule.

Obviously I think it would be a huge buff to all legends. That second ragavan would no longer wait in your hand for a removal spell. Agatha’s soul cauldron would be awesome in multiples. Mox Opal can suddenly enable itself. Boseiju, Phyrexian tower, and other legendary lands suddenly have no downside. You can now start stacking Thalias in multiples to really tax people.

What’s the most broken thing you think would be enabled by this change? Would it need to get the ban hammer?

I don’t think it’s likely they would make this change retroactively but I thought it was interesting to think about.