Interesting ideas PA. I wanted to get into this discussion but didn't know where to start, so I looked up the word perfect at wiktionary.com. Here were the definitions-

1. Fitting its definition precisely

2. Having all of its parts in harmony with a common purpose.

3. Thoroughly skilled or talented

4. Excellent and delightful in all respects

5. Representing a completed action.

I think the first two definitions pertain to this discussion the most. When you say nothing in the universe is perfect, going by the first definition, that would be the same as saying nothing in the universe fits it's definition precisely. But what is the definition of the universe? If the definition of the universe is to be an imperfect system, and nothing in the universe is perfect, then it would fit it's definition and therefore be a perfect universe. The same with the second definition - having all parts in harmony with a common purpose. But what is that common purpose that it's trying to attain? You mentioned that only concepts are perfect. Well I feel that the idea of perfection is something we invented to compare our concepts with reality. I think the idea of perfection only appears when there is intelligent life to carry out measurements. Because then we have a perfect concept in our mind and can compare it to what is physically infront of us. The idea in our mind is going to be clean cut and solid, but in real life it's made out of particles and will therefore be messy when it comes to measurements. But I think it's all relative. I mean we could change the definition for a liter, so that the word liter meant "roughly a liter", and then all the liters of water would be perfect according to the new definition.