Their icons are not good. Too glassy and cartoony and too many gradients. They don't look modern, they look like icons for a kids app from 10 years ago.
They are planning to adopt Font Awesome as the default icon theme. Right now they are still using the old Oxygen set.
And at that, you can pick your own icon themes anyway. There are Hycons, Numix, Faenza, etc. I do agree defaults matter and the Oxygen icon set is gaudy, but it shouldn't stop an HN user from trying it since you can change them.
