Maybe it would be better if the participation goes to a critical number, for example 60% that the system auto-fires the half of the delegates that currently are not producing blocks and have the worst reliability compared with the other half. Only for extreme situations like that...
i am not sure if auto-firing of delegates that are inactive is a good thing .. but maybe a 12h penalty .. there can always we a power outage, a screw up during update, or some other kind of screw up .. that result in missing a block ..
however .. an auto-fire for misbehaving (in terms of double spend) delegates is a must IMHO
we should also discuss a penalty for delegates that produce forks due to two unlocked wallets ..
this might be a good idea for a separated dev/delegate hangout session IMHO