1) People in the past would have lost a lot of their teeth, especially in the lower classes. Thnk about it: no fortified milk, toothpaste, flouride-enriched water etc.
2) People would have been a lot shorter. With the agricultural revolution, despite being the "cornerstone of civilization", the standards of living dropped hideously, people ate a less balanced meal, so they were less healthy, had greater bone lesions due to disease (at least in their remains), and nearly lost a foot of their height when compared to hunter-gatherers who inhabited the same region.
3) With regards to filth, I'm sure people would have been dusty, but the fact that many did not use detergents or soap on their bodies would have meant that they actually would have had less-oily hair and less acne (as these products do irritate the skin, and cause glands in the scalp to secrete oil).

When I was younger I used to think "Man, Ancient Egyptian women must have been hot" until I realized they had all these problems, and as a bonus, also shaved their heads....

I probably would have gone with a Thracian/Dacian gal, seeing as how they had their diets supplemented with more protein and milk due to the transhumant pastoralism some of them practiced; I may also be slightly biased, coming from Romania.

Well, that would have turned out well until she would decide to sacrifice my first-born as a messenger to Zalmoxis...