It's true that significant use of downvotes on bad actors would cause an upscaling of rewards on all other content. It's something I should have added into my estimates. However the impact of the SPS / 50/50 and CLRC all act in the opposite direction and those impacts will dominate heavily for small earning posts.

There are too many moving parts to do a simple calculation of payout for a particular vote assuming all else is equal and expect that to be remotely valid. It isn't.

Here I would respectfully disagree. Most of the proposed changes have clear and measurable impacts and getting an initial assessment prior to behavioural changes is useful and a pretty solid starting point. People can then judge how they think behaviour will change those figures.