I have noticed that during this time that Epcot is less packed on Mondays, Wednesdays, and Thursdays. A.K. is less crowded during weekdays as opposed to Saturdays or Sundays. I think that MGM has seemed less dense on Tuesdays and Fridays. Ususally, the park crowds are large right at opening time so you will see a sizeable crowd especially if you decide to go to a park when it is its' early entry mronings.
In all the times we have gone down during this time we have never gone back to the hotel during midday even when we traveled with family members with children. We have always made it a point to take as many breaks during the day as needed, along with finding shade, sitting down while getting something cold to drink, taking advantge of as much air conditioning as possible along with taking a really slow and laid back style of touring the parks.
We have never been the commando type of WDW visitors who have adhered to a prepatterned schedule of going straight from one ride to another ride and haven't had a regular strategy of attending all the attractions or shows. So, we don't get tired as easy because we just go with the flow in experiencing everything throughout the day along with taking small breaks here and there so for us a rising desire to go back to the hotel hasn't occurred.
Also, since the weather in August has been somewhat akind to our home, it has made the heat of WDW during this time a lot easier to bear having been accustomed to growing up with similar summer temps (think that's an additional reason why we haven't had a need to leave parks for the hotel and then return later).
So, you might want to play it by ear and see how you adjust as the day progresses. I think if you can definitely resign to taking as many breaks you or others may want for however long, as well as adopting an open approach to touring the parks by remaining unhurried, leisurely paced, and without sticking to a set in stone schedule when seeking out rides/shows, along with constantly replenishing yourself with water/juices, and enjoying as much airconditioning as you want, you may not feel a need to go back to the hotel at all like we have always found.
However, if you are traveling with kids that are used to a specified nap schedule and have gotten worn out by midday, then returning back to hotel for you will constitute a priority. So in all, I think it is totally possible to tour the parks without an afternoon hotel break if you do not rush through with breakneck speed and partake in numerous timeouts but you may want to see how well you feel in the moment once there. Also, usually as the evening arrives, I have not noticed a significant difference (decrease) between crowds during the day or at night in August.
I have been hearing that the parks are supposed to close at 7:00pm at the end of August this year but hopefully this will change because the familes that do decide to go back to the hotel will not have as much time left when returning in comparison to previous years.
Hope this helps also.