Should you practice Tai Chi with your eyes closed?

Yes and no.

The eyes direct your intent and the intent directs the chi.

By looking at the yang (husband) hand you are cultivating the chi to that point for striking and pushing etc.

By looking to the yin (wife) hand you are cultivating it for yielding, pulling or shaking etc.

By looking at the opponent you are cultivating the technical combative use.

By closing them you are cultivating the internal use for sensitivity and allowing the chi to use its own intelligence and give you insight to its use for health and internal power.

Train all of them.