You have to assume the pilot is aware of the local terrain and is therefore not going to request a heading that will put them in a dangerous position.
Therefore: if the pilot asks for a certain track or heading for weather: "approved"
As an ATCO, I only tend to have to worry about separating against other traffic. Modern aircraft, with latest generation weather radar and EGPWS, can probably plot safer routes out of my airport than I can in Cb activity.