One of the big issues with experiments is how much value they really drive, which is the real effects. In many situations we do A/B testing for changes whose real impact is a fraction of a percent of the tracked metric. If anyone followed the discussion about p-hacking in science [1] should really start wondering if the way we run experiments, considering the little changes we see, is not nearing p-hacking, especially when I see this ideas floating, and if we don't need to find more significant way of running our experiments.
[1] One of the first article I found about the issue http://journals.plos.org/plosbiology/article?id=10.1371/jour...