This is similar to my thinking, but we don’t require any forks, just smartpools.
We can create smartpools that include a slush fund that pays out to miners when a sharp and sustained increase in difficulty is detected on the network.
The slush fund can be funded both or either by a constant fee on the mining pool, say 2-3% additional to dev fee; and by an opposite rule when the difficulty drops quickly (Say 20-50% of the block reward.)
This combined with a PPLNS reward model ( or at least one that can track loyalty over a long period of time, pre difficulty increase) will enable miners to see smoother rewards as the difficulty rises and falls WITHOUT decreasing the security of the network or removing voting power from miners.