Despite superficial similarities between cricket and baseball they are very different sports. I don't suppose that the switch hitting of Kevin Pietersen made any headlines in America - after all Micky Mantle did it all the time. However, cricket is an asymetrical game in a way that baseball is not and 'left' and 'right' are very different.
Whether you are a left-handed or right-handed bat the 'leg' and 'off' side are very different and different laws apply (in cricket the rules of the game are known as laws). What happened was that as the bowler (pitcher) ran up to bowl (pitch) the batter switched from being a right-hander to a left-hander and promptly hit the ball for six (roughly similar to a home run). Why did he do it? Because the fielders were asymetrically spread. Instead of having 5 on one side and 4 on the other, there might be 7 on one and 2 on the other; by switching the imbalance comes into the batter's favor.
The real problem is that 'leg' (left for a right-hander) and 'off' (right for a right-hander) are treated differently under the laws. For example, Law 36.3, does not allow more than two fielders to be behind the bat on the leg side. On the off-side there can be as many as the bowler wishes behind the bat on the off side. Since it is the usual practice for there to be as many as 4 or 5 behind the bat on the off side, if a right-handed batter changes to a left-hander once the bowler has begun to bowl, he must still be treated as a right hander else the play would be illegal because of the two behind the wicket law.
All batsmen enjoy a measure of protection on the leg-side. He cannot be given out leg-before-wicket if the ball pitches (unlike baseball, in cricket the ball is meant to bounce before it reaches the batter, in order to give the batter a greater chance of missing it) the outside the leg stump. If he switched his leg stump becomes his off-stump (or does it?) and a the LBW law is confused.
Chobham armor was a development in the armor of battle tanks. It was designed as a way of stopping certain types of projectiles penetrating the tank. The projectile manufacturers countered by making heavier shells out of depleted uranium, which would have more momentum when they hit the tank. In fact the same manufacturers were often producing better armor and better projectiles at the same time as a sort of game. It's called the market.
Stephen J Gould wrote a fascinating essay on how in baseball the advantage would swing from batter to pitcher as the pitching mound was raised or lowered. Golfers also wage a constant battle with course designers - often you are better playing a course left handed as they are frequently designed so that the hazards mainly restrict right-handers. In cricket once a batsman gains supremacy the bowler will develop a new strategy to restrict him. In the famous 'bodyline' tour of Australia in 1932-3, the England captain, Douglas Jardine, developed what he called 'leg-theory' in an attempt to restrict the greatest batsman of all time, Don Bradman. by bowling at the body rather than the wicket. In the 1960s the West Indians took this to new lengths by bowling very fast at the batters' head. Batters retaliated by donning crash helmets. The early development of the 'googly' or 'Bosie', an off-break that looks as though it ought to be a leg-break was another strategy developed by bowlers to beat the batsmen, and the recent successes of spin bowlers Shane Warne and Muralitharan show how bowlers have gained an advantage.
Switch hitting exposes the batter to greater danger. Mike Gatting, a former England captain, tried in disastrously in the 1980s against the decidedly average spin bowling of Australian captain, Alan Border, and the subsequent reversal of fortune probably lost England the test match. Despite the difficulties with the laws, I think that switch hitting is here to stay and adds to the vitality of the game.