I think you could viably chuck in anything for Season 16. I remember most of the episodes being bad-awful except for a couple of exceptions (France II, Seychelles and maybe the first China leg).
Other bad ones I remember include Season 23 premiere (really poor and almost made me stop watching), Switzerland from 22, 21's premiere and second episode ( both really bad except for finding the lady with the abacus), S19 Ep 5 (Thailand II, although this was apparently done at the last minute as a backup leg), the Vietnam and Cambodia legs of S15, S11 premiere etc. Some of the late-game family edition legs weren't so great either.
On the other hand the best legs are: Season 2 finale, Season 3's Switzerland, Season 3 Vietnam, Season 5's Russia, Egypt and the Philippines, Season 6's Norway, Sweden and Xian, Season 12's Taiwan, Season 13's Russia, Season 14's China (all of them, particuarly the last one), S15 finale, Season 17's Russia and Oman, Season 18 China II, Season 20's Paraguay and finale as well as Season 21's France and finale.