If the issue is restricted airflow from mud, I would think a thicker radiator would still suffer the same restrictions.
It does, but triple bypass basically forces water to traverse the cooling fins three times instead of just once, so if portions of the radiator are functioning better you'll get more cooling overall. Some of the heavy duty radiators have more spacing between fins so mud can pass through instead of getting lodged in the fins. I have one of these in my Can AM and it completely solved my overheat issue.If the issue is restricted airflow from mud, I would think a thicker radiator would still suffer the same restrictions.