You are right where I was last July when I decided that my faithful old Giant Cypress DX was too heavy and slow. I needed a road bike. I made that purchase, loved it and sold my hybrid. A few months later I missed the hybrid. Then I purchases the mixte. Welcome to mixte fever!
Is it possible to have ONE bike that does everything you want? For me, I don't think so, or at least I don't know what it would be.