Further down the line, having multiple legendaries can add a new layer of character customisation as those utility legendaries can come in useful in higher difficulty mythic keystone dungeons and raids. Being able to swap around these legendaries to unlock new strategic options to tailor your character for specific situations. This is not to say that the utility legendaries will be required for such content, just that they provide an additional layer of strategic depth.
With the current system some people won't even have one. You're talking about people having a collection of legendaries they can choose from. Don't want to be disrespectful, but LOL.
Not saying you're wrong, but that's like asking should I drive my Ferrari or Lamborghini today. Oh, wait I have neither and will likely NEVER have both.
I see what you're saying, but on the flipside we're not even 2 months into Legion yet. I get that not having a legendary, or having a less than ideal one, is pretty frustrating at the moment. But, zooming out a bit to look at things in the long-term, by the time we are say... 10+ months... in, it is very likely that most players who have been playing regularly will have more than 1 legendary at their disposal.
I feel like there is something worse than this still. Playing a tank main focused on mythic raiding, playing a class that benefits so little from crit its borderline worthless, getting the wonderful "Sephuz's Secret". Honestly its so bad that in any content where i need survivability it gets swapped for a ring 45IL's lower because even when i can proc it 1400 mastery or versa is just better.
I feel bad for people that dont have one, but at the moment for what i want to do in the game, i dont have one either.
I guess at least it means i cant drop it twice.
Like I said, we recognise that some of the more utility orientated legendaries aren't great right now, and those are under review to give them a little bit more razzmatazz. At this point in time I don't have anything more specific I can share.