Ive discovered that it is evidently the implications of an extra time dimension that causes the notion to be shunned by physicists.
With a single time dimension we have a timeline where order exists, i.e. before this, after that. Add another time dimension, and that timeline becomes a plane and there is no past or future hence cause and effect get muddled (physics must have causation) objects travel faster than light, etc.
Nevertheless, a few brave scientists have ventured into the possibilities and the results are quite interesting.