One consideration is printer ink. The current design requires very little ink to print.
A properly designed website prints dark text on white just fine. No issue.
Another consideration is page loading time.
Dark colors load just as fast as light ones!
Yet another is readability on a phone with adaptive design.
The current website is NOT responsive (mobile-friendly) so this would only be an improvement.
And finally, I care about content way more than appearance.
It is 2017; we can have both!