"A botnet could abuse it big time"
This was the reason for having exponential, instead of linear, voting rewards on Steemit originally. That changed with HF 19.
" I've always had this nagging feeling at the back of my head that there's something not quite right about the whole system"
Yes, as have I. The game theory is not aligned with the desired community behavior, which is why I wrote Code Is Law.
Hey! You're back! For a while I thought you got so disheartened that you left, or something!