Yup the linear thing is almost irrelevant, the 400% increase of potential power per vote is somewhat drastic, but very exciting :)
I wouldn't care if they increased it from 0.5% to 100% either lol. As long as they would give everyone the slider that is...
I think it's done for the little people. Users with > 500 SP will have the slider for more accurate curation. There are so many more little people (over 95% of the user base probably) that will all have 4 times as much power because they have no slider. We'll see how it goes, it can't be that problematic. More problematic than the current implementation seems impossible to me. It's horrific right now.