To repeat the previous reviewers opening remarks: this is one of THE best world heritage sites. Why only 4 stars? Because there are so many Roman ruins on the list already! You see one amphitheater you've seen them all, of sorts.
The site is so vast it will take you 3 hours to explore and to think they haven't excavated many sections including the stadium. It's so well preserved as it never had any wars and the people lived peaceful in Dougga until the 1960s(!) building new houses within the ancient walls. At that point the culture minister finally stepped in and asked to move their shit out and you only see the ruins now. There is no money for further excavations at this point but often the gardens are restored for visitors.
The most unique thing about the site is the use of a weather compass, showing the climate depending on the wind direction. It doesn't look clear on pictures so I didn't include one. Also the site shows that stones with donation inscription for temples (they were apparently not always provided by the Empire) were reused as other walls as needed, as part of a refurbishment of town I suppose.
Overall the well maintained buildings and historical significance of having survived so long is definitely worthy of inscription.
Two things you should note:
* There are TWO entrances and the southern one doesn't open until 10am. You can still arrive here and a caretaker will take you to the northern gate to pay the entrance ticket. If you are coming from Tunis then this doesn't apply to you.
* You should to use a guide. You will miss soooo many details about the place otherwise. I think that's maybe why one would rate it a bit lower as "just some more Roman ruins". For this reason I recommend a guide AND for females I have the best guide suggestion: a lady called Bejaoui, of course you can still hire her as a male traveler but for me it's so much more relaxing to have a women guiding me which is why I mention it. As soon as you arrive some guide will approach you nicely so if you don't care who guides you then just show up. Bejaoui is super knowledgeable about Dougga, her specialty, speaks fluent English, French, Italian and Arabic, and can tell you exactly how much you need time tailored to what you want to see, as the site is super big. She can also meet you at the south gate if you are coming from there. Reach her at Whatsapp +216 97 871 887 or +216 28 248 352 or imed0021@hotmail.fr Satisfaction guaranteed :) after 3 hours I can say I was surprised how much I can learn for something I only expected to take 1 hour looking around.