Linear rewards isn't what caused the situation with bid bots today. If we switched back to the old curve now that bidbots control the majority of the stake, we would be in an even worse shape as the real contents (ones who dont pay for bidbot) would earn $0.00 and the network would practically become a racket.
The issue is how easy it is to game the distribution algorithm today, and to determine exactly the payout the vote will generate. It's 75% because of author rewards, and the rest is because curation is way too simple and flat in terms of returns for big stake holders. My intent is to try a new algorithm where bots struggle to be efficient, even on linear rewards, without having to trust the whales to maintain the system. Linear rewards is a dream we should try to make come true :)