Blizzard is updating Legendary items in their next World of Warcraft patch. On live servers right now there is a problem that some Legendaries are extremely effective and others are ... really bad. They have decided that the gap should be closer, and I quite agree. It isn't that they should all be the same, but just that there should be a real argument for using each one depending on your situation and priorities. Each character can only use 2 Legendaries so the balance between them is very important.
For example, as a Retribution Paladin I currently have 2 Legendaries that give me a 5% dps increase. (I don't own either of them, but they exist.) There are also a couple of Legendaries that give decent utility, and then a couple that are absolutely garbage. Generally the people who are really competitive, top tier players all say that the 2 Legendaries that increase dps are good and everything else is irrelevant and has no use. I tend to disagree with that stance because not everyone is pushing the hardest content with barely enough gear.
As an example, there is a Legendary that saves you when you die and gives you a big damage shield. This is excellent in any situation where dying is the problem. However, if you are trying to do a boss that requires 105 dps to beat and you only do 100 dps, then you simply have to take the Legendary that gives 5 dps. You can't take the Legendary that saves you from death because you just have to not die. This is the situation a lot of top raiders are in. They can't win if anyone screws up and they play like crazy so they are doing bosses that their gear is just barely adequate for and that extra 5% is what will let them win.
In my guild though we are doing much easier content. We have a lot of casual players. Most of our kills happen with tons of raiders dead, especially first kills. We don't play over and over until nobody makes a mistake - we just play until we make few enough mistakes overall that we win. In that environment the Legendary that saves you from death is *amazing*. We don't need 105 dps to win. We just need 85, so if you live throughout the entire fight you have done your 100 dps and easily beaten the benchmark. This is a fine scenario. I don't need 10 Legendary options that are competitive for the hardcore raiders, I just need 10 Legendaries that do something useful and have their niche. While using a Legendary like the one that saves you from death you might get mocked by the hardcore types it is still useful for them and great for people in my situation.
That sort of thing doesn't describe all the Legendaries though. For example, one of ones I have is called Chain of Thrayn. It heals anyone I cast a Blessing on for 15% of their health. I have a Blessing to use with it which I can cast about every 30 seconds, so I heal about .5% of a person's health/sec using this ability. A healer heals about 15% of a person's health per second, so this is worth about 3% of a healer. It doesn't sound so bad thus far, but there are a ton of downsides. First off is the problem that I need to take time to cast the blessing, and doing so costs me about 3% of my damage. Then I need to pay attention to other people's health and figure out who I am targetting and that costs me time I could be thinking about other things. It ends up shifting damage to healing in a way that isn't profitable and it costs me brain cycles to do it. Plus if I do this I lose access to that Blessing for other utility. On the flip side it means that if I use that Blessing randomly (which I do, at times) then it is helpful without cost.
The net assessment of this Legendary is that it is absolutely wretched. It provides a modest sized heal very rarely and not when I want it. Compared to 5% bonus damage it is a joke. There simply isn't any circumstance in which this Legendary is actually a solid choice. If they increased the heal to 50% instead of 15% then we would be looking at an item I would actually be excited about.
Blizzard noticed this and is changing Chain of Thrayn to improve my damage by 25% and healing by 70% during Avenging Wrath, which is up about 25% of the time. The new functionality is really interesting and while most people will just use it for damage I think there are a lot of powerful healing applications too. In any case it will be competitive and I won't be sad to own it anymore.
Overall I really approve of the direction they are taking. There are still Legendaries that are kind of niche, and ones that have utility I don't think a lot of people are looking for. However, all the absolutely trash ones are being buffed, and instead of 2 Legendaries standing head and shoulders above the rest there are going to be a bunch of options. I like that, because it means once you have a few Legendaries you will have some good stuff. Nobody will end up with 3 Legendaries and not have a single one that is decent for them. It isn't a great feeling to know that you are doing 10% less damage than you could be and that nothing you can do will change it until you get the perfect drop.
We don't need all Legendaries to be the same. Having some that do wacky but useful things is great. We just need a selection of choices in the top tier so people can do different stuff and be ok, and some fun things for those who really want to branch out. The first iteration of Legendaries failed at this, but the new set actually looks really good.
So far, so good.