Changing from 40 target votes to 5 without changing regeneration days allows Steem to ease into more optimal ratios for quality curation.
People are stuck on the "40 target" while the key point is "without changing regeneration days" This will contribute to balance voting power by diminishing the impact of whales. The intention that underlines this feature is it seems to distribute more voting power accross users.
I think this is an interesting feature that has to be tested. Let's not prejudge the outcome, we cannot anticipate how each one of us will be affected by this change.
I think that overall the system of weighting votes by stake helps keep the system more fair, though for moderating the effects of whales votes, I think that your idea of modulating vote power based on a users posts and the votes on them (and their rep) would help diminish the giant whack that whalevotes give, and it is not a good thing entirely because it narrows what hits the top. If someone is making a lot of effort and getting good traction posting, versus a whale with 3 posts and a million snarky comments, their vote should matter more than it currently does, and the whale's less. I refer to a particular whale when I speak of this, who has a post whining about being hounded for votes by people. In effect, this would placate this whale and make less people hound him for votes. Stake based voting is very good, and I don't want to see it diminished too much, but I think that reputation and upvoted posts should be a parameter in the formula for generating rewards. This is a means to increasing quality contribution.