One of Eligius's advantages is that you can create separate little stashes of 'virgin' coins. I would have thought this an appealing point of differentiation for Eligius against other pools.
If you have to mine to a single address and then transfer coins on the blockchain - you tie these stashes together in the public record.
It wouldn't bother me if payout to inactive addresses was low precedence and slow.. but it should be automatic and complete.
Its not that you have to mine a single address. The CPPSBAM method only effects inactive miners in times when there is no buffer available. So, during average or lucky times for the pool, you could still switch addresses without any negative effects.