I think season 17 really showcased some exciting and interesting tasks. To me, I think they were quite challenging for the teams, sometimes they really pushed them to their limits.
I think where the tasks were simple was in fact seasons 12- 16. For instance, in season 16, we had painting a 15cm x 15cm square, getting the ingredients for the kuchen ( the hardest part for Cord seemed to be carrying it all at once
) crawling on the ground and bike riding in France *yawn*, swimming to a buoy a short distance away and getting a bottle in the Seychelles, two coconut tasks in two consecutive legs and two counting roadblocks with almost the exact same number, almost in consecutive legs. Not to mention what I consider the worst and easiest final leg memory task in all of TAR history. I'm sure the teams would have thought they were difficult, hard and challenging - but to me, a viewer, they seemed not so "amazing". Some of them looked fairly easy to me, quite a bit easier than past seasons.
I really think the tasks in TAR16 were simpler than earlier seasons (and by no means do I mean to particularly single our season 16, I could do it for 15, 13 or 12 if you like
) and I'm glad season 17 gave some more difficult and not so straight forward tasks. I think to truely determine whether tasks are getting easier I'm going to have to watch TAR18 and see whether I thought season 17 was a standout or if it was the beginning (for me) of tasks really becoming more "difficult".