Don't agree with the OP at all.

The fact that Sally, a woman, came in second last week proves that a woman CAN compete. She beat out 3 men, for crying out loud.

As has been discussed on these boards many times in the past, the challenges are determined long before the casting is completed and there is no way they are designed to favor individual competitiors. The challenge sites are planned and some are constructed before filming begins and casting isn't finalized until just before the cameras start rolling. The producers have no way of knowing who will or will not be in the game at this point and certainly have no way to know who would have the HII or even who would have been to Exile Island to look for it.

I do think that when they cast someone like Terry, they know he could be a real challenge beast, but they have no idea he will still be in the game at this point. He has lasted a lot longer than many many alpha-males, who are typically eliminated at around merge due to the potential danger of them dominating challenges.

Lastly, although the last challenge required swimming, it was mainly a mental challenge. A women who smims well can do better than many or even most men who do not swim well. Swimming is mainly technique and fitness and either gender can swim fast as long as they have the technique and fitness. I am a swimmer and I can swim a lot faster than many men who would beat me in most other physical contests. So I would say the last IC was not really that physical, at least not brute strength. It was technique/skill and mental.

It would be pretty hard to design a challenge that Cerie could do well at. She has great social skills, but physically and intellectually she just isn't in the running.

This last IC wasn't so much a test of one's physical strength as much as a test of one's memory skills. By Terry nailing the puzzle on his first try he won because of his superior memory skills (which by the way Aras could have won since HE had first crack at it).
As for variety in the challenges I think last week's challenge had a diverse amount of variety. It started out digging through the sand and trying to slither under a pole. How was that catered to Terry's "strength"? Actually it was more catered to a player built like Olive Oil (ala Sally). And that challenge also involved solving a puzzle too.

Historically there have been several challenges that have focused on a balance beam which is CLEARLY advantageous to the female competitor. Without going specifically into other types of challenges,i.e., word games, trivia contests, sliding a disk across a schuffle board, etc, etc,etc...I think the show has done a great job diversifying the individual challenges.

So why has Terry been dominant? Two out of his three individual immunity wins were helped by the fact that Casaya just plain QUIT. Personally I feel the challenges should always benefit the Survivor who puts out an optimum effort and gives 110% no matter what. Whereas it's no doubt that Terry possesses more atheticism than anyone else this season, I would credit his success thus far to the fact that he has tried the hardest on a consistent basis from day one.

Conspiracy theories are lame. The challenges are decided upon well before filming starts. Aras was the first one to complete the puzzle last night, and Sally had a crack at it too. Terry won because he remembered the puzzle in one attempt. Casaya did him a great favor by choosing to eat instead of competing, but he likely would have beaten them anyway. Remembering 7 logos in order in one shot while looking at them once under water is very impressive and has nothing to do with physicality. Terry is physically AND mentally the strongest, and he also competes the hardest.
Now, it IS true that the challenges this season have been pretty physical, but considering all the women on the show, except for Cirie, are pretty strong, it fits the cast well. Plus, as I have said before, I think surviving in the wild IS a physical exercise, and therefore, being strong, or at least physically capable, SHOULD be an advantage on Survivor. Yes, it is social game, but again, it isn't Big Brother either. Competing is a fundamental element of Survivor, and the better competitors typically do have an advantage (at least until F2).