Another thought: Currently there's a problem with very large transfers, since guarding them against double-spending can take days (at least) of confirmations. Paying transaction fees won't help because it can only get it in a block faster, it can't significantly affect block generation rate afterwards.

With the new system (work/stake hybrid approach), senders of large amounts can include a signature fee in addition to the regular miner fee, which goes proportionally to stakeholders who sign the block in which the transaction appears. This will incentivize stakeholders to sign, making the transaction secure without having to wait for more confirmations.