Multi-pools that are just for some reason able to attract “normal” delegations and exchanges are two very different problems, in my opinion.
Exchanges having lots of stake can hardly be countered by incentives/tweaks aimed at active participants choosing a stake pool. It’s people buying ADA on exchanges and just holding them there without any interest in participating further. I’d see two ways in countering that, but both do not have much to do with staking/rewards/delegation. 1. Really participating could become so interesting that enough people move from exchanges to their own wallets. 2. ADA could continue to underperform in short-term “value” craziness so that all the cryptocurrency gamblers just go away.
How do they do that, anyway? The latest calculations I have seen were that even a fully saturated, fully pledged private pool “only” gives something like 5.5%.
Best proposal I have seen is: CIP - Shelley’s Basho-Voltaire decentralization update