You may be right, but quite a few European tour operators don't go in the summer, including all the Scandinavian ones. The reason for this is that all the classic European destinations, such as Spain, Portugal, Turkey and Greece, are the favorites for a summer holiday, not in the least because of the shorter flying time and much cheaper insurance. It is much more difficult to find warm weather and nice beaches in the winter - hence the popularity of the Dominican Republic in the European winter months.
And when I requested rates of the big all inclusives - some of those were in the Bavaro area - the cheapest rates were in the summer. This may just be your solution: To book a flight and the hotel yourself. It is quite easy to do through the Internet nowadays. You can still get it all inclusive at a very reasonable rate, especially if you shop around a bit.
Regards, Susanne