Según mi nivel de inglés me ha permitido entender:
Parece ser que cuando tenías posibilidad de conseguir un legendario y no lo conseguías, tu probabilidad de conseguir uno aumentaba un poco. Eso sucedía hasta que tenías 4 legendarios. Ahora sigue pasando aun teniendo 4 legendarios.
Fuente: http://us.battle.net/forums/en/wow/topic/20752276726?page=9#176
Happy Thanksgiving, everyone. Let's talk a bit about legendaries.
From the beginning of Legion, we've deliberately been pretty tight-lipped about how obtaining them works, because the best thing you can do to get them really does just boil down to "play the game and do the max-level activities you enjoy most." It was meant to be a background universal reward that would occasionally offer a surge of power to complement the transparent and omnipresent Artifact and normal itemization systems. Obviously, as we sit here reading posts speculating whether it's better to delete unwanted legendaries to improve your chances of getting more, there's a lesson for us to learn from how that approach has played out. (PS: Don't delete your legendaries. The system looks at what you've gotten, not what you have.)
We've also been pretty conservative in our design, with the intent of loosening the reins as time went on. With a system of this scale that spans all max-level activities, we couldn't be certain that we'd tuned it correctly based on data from thousands of people playing our beta for a few hours a week; it'd inevitably be different in the live game with millions of people playing in far more focused ways. And we knew that if we erred on the side of legendaries being too common, we could easily end up in a situation where some people (whether lucky people, or those who played the most) were flooded with them. If that happened, it'd have been a mess - a chunk of the playerbase would've had bags full of legendary items and no more to look forward to for months to come, and if we'd tried to "fix" it after the fact, then everyone who hadn't taken advantage of the generous period would have felt forever behind.
So we started out stingy, since if we erred in that direction it would be far more fixable. (We've since increased legendary drop rates in general, in patch 7.1). We also put some measures in place to reduce the gap between the very luckiest player and the unluckiest player. Luck is inevitably a factor in games like this, but with millions of people playing the game, if we allowed pure randomness to go unchecked, there would inevitably be some players who played hours every week and literally never saw a single legendary item. Thus, the so-called "bad luck protection" that improves your chances a bit each time you could have gotten a legendary but failed to do so.
As its name suggests, the "bad luck protection" system exists to protect the unluckiest players from the cruel fate of the dice. Those who were on the other end of the spectrum in terms of good fortune, we figured, didn't need a system to help put them even farther ahead of the rest of the world. And we drew that line at 4 legendaries, initially, planning to raise it as time went on. Once you'd gotten 4, you could absolutely get more, but the invisible hand of "bad luck protection" would no longer help you. Almost by definition, if you had 4 legendaries in, say, early October, you were super-lucky. You didn't need help getting more.
What we genuinely did not anticipate was just how much some of the very most dedicated players would play, mainly in pursuit of Artifact Power. By mid-November, we started to hear questions about whether there was some sort of 4-legendary limit, and we realized that there existed a group of players that had done so much content that they actually had an expected legendary count of around 4. They hadn't needed to be unusually lucky to get there. (Note that this is a very small group. They're overrepresented in these discussions, because this issue concerns them, but we're talking about hundreds of people out of millions.)
So we removed that soft cap just over a week ago. "Bad luck protection" now applies indefinitely. Most of the players in this category have probably been focusing on Mythic Trial of Valor for the past week, and since wiping repeatedly to raid bosses during progress sadly can't award legendaries, they haven't had a chance to see the effects of the change just yet. If/when some players get to a point when they have every legendary available for their spec, then so be it. They certainly will have earned it, and there will be more coming in future patches. The Unique-Equipped limit keeps the power gap between the haves and have-nots reasonable, and we'll continue to adjust the effectiveness of the outlier legendaries (coming up in patch 7.1.5) with the goal of keeping them exciting but not gamebreaking.