I have not had a paper ticket between MIA and SDQ for over 2 years from AA. Certainly not this March or January or last year in October, August, May, etc.
I am not sure what you mean by the DR "needs" ( or not) e-tickets. When you check in they need your name and ID, there is no need really to even have the receipt or e-mail for the e-tickets nor has there been for a long time.
As for the immigration authorities they never ask for one coming in or going out.