The only thing that worries me about this is, with previous balance changes, rivens that already had their rolls weren't changed, this was fantastic because it meant that they couldn't reroll without their riven being effectively nerfed, but doesn't undermine the time they spent getting the hundreds of thousands of kuva required to get it to that roll.
This looks like it can be applied to existing rivens retroactively, changing the max stats of the Riven when equipped is much different to changing the max stats of a Riven when next rolled. Which isn't going to make many people very happy, especially when you already had a (albeit worse) pre-established buffing and nerfing system in place prior to this.
I like the changes, I just fear for the people who spent days farming kuva for their Tiberon riven
I haven't been paying attention to riven re-balancing since the first wave, and at that point, it sounded like this was what they were going to do and I just assumed that's what they did. Thank you to all who informed me politely.