The law actually specifies a maximum wattage, which back before all the new technology like LEDs and Xenons actually did limit the brightness… But the laws haven’t been keeping up with technology for quite a while…

Probably because most of them aren’t even under the same rules as cars: https://www.jalopnik.com/2111008/how-non-passenger-work-vehicle-became-family-car/

I disagree, depending on the animation. There was this BMW SUV (I’m not really sure which model) driving around here and their turn signal looked nearly indistinguishable from a sunlight reflection. It faded both IN and out, with a slow transition across, and I personally barely could tell it was on unless I was staring directly at it. It doesn’t catch your eye like a turn signal should.

I think animated signals are fine, but there should be some rules to it, like requiring it to flash on, but allowing fade outs or transitions.