Okay, well I'm curious - especially to see what kind of information-processing does not count as what Dennett called "maximally bland computationalism" - which includes e.g. quantum computing.
And I don't think Dennett is a pessimist - he still clearly thinks the world is a wonderful place. You might think the world is wonderful even if it doesn't have unicorns in it without thereby being a "pessimist" for saying there are no unicorns, and Dennett similarly thinks it's wonderful even without qualia in it.
But I will await your neat solution!