I dont think that was a "constructive criticism". He didnt give any examples as of what would be "good design". Your site looks pro in IE/FF/Chrome/Opera and Safari. Layout is clear and simple. Love it! Navigation is straightforward. Cool!
At the same time though, I realise that sometimes people don't have the time to phrase things in a nice way, but at the same time still have valid criticisms - and I'd rather hear the criticisms in the first place than hope they'd be written in a nice way - if that makes sense (it's late here, and I'm not sure which space my brain is in) :)