Is there any country that requires window blinds to be open for takeoff and landing?
There is a regulation which indirectly covers it. Certainly in the UK and I'm pretty sure in the US and EASA land, it is an offence to not comply with the lawful instruction of a member of the crew. Therefore, if you are asked to raise the blinds, it is a legal requirement for you to do so. 

Failing to comply with an instruction which is not itself illegal is an offence. Rarely used but it has been. Usually, the cabin crew will just mark you down as "idiot" and do it themselves. But, if it is clear that you understand and that you are able to comply, you might be removed from the flight and prosecuted. Generic laws like this, e.g. "dangerous driving" are there to provide for reasonable action when a specific law does not apply. 

A valid defence would be to demonstrate that you were unable to comply to the extent that the prosecution is unable to convince a jury of your peers to find you guilty "beyond reasonable doubt".

So, in summary, albeit indirectly, it is a legal requirement for you to raise the blind when asked to do so in the UK.