If there is a real purpose behind adding the custom tiles (examples: sewer tiles, prison, old-looking town (if you traveled to the past for some reason)...), it's great to have them.
If the reason behind adding custom tiles is "FR tiles look boring, let's switch to DP tiles instead", I don't really see a point in adding them.
If the reason behind adding custom tiles is "FR tiles look boring, let's switch to DP tiles instead", I don't really see a point in adding them.