Just my opinion, since I feel this is an interesting topic to talk about...
One of the aspects that makes raiding (and PVE) so exciting is the fact you don't know what will drop and when. It's not the first time I find myself in a position where I'm chasing a particular drop and it just keeps evading me *forever*. It is, indeed, rather frustrating when you consider it from the perspective of the person that wants to finally get that new shield or bracers or whichever.
On the other hand, though, and this is where I think it'd make PVE less attractive is that, if you can plan for certain which upgrades you'll be getting, and when, then, there might not be enough reason to progress past certain bosses. Say, your guild has a hell of a time trying to kill Megaera
. Under such a system, you'd still be rewarded with a Tier 15 helm token after some time, despite that one dropping only from the Twin Consorts
. And therefore, losing part of the incentive to keep pushing your raid progress to that boss as well as getting rewarded just for showing up on the instance and doing some progress.
Also, the Valor Points
items do ensure you'll be able to get items within a reasonable timeframe, of course, you might argue you'd like to get gear faster, but the fact is that you can control to some extent when you'll get something.
Putting those things into perspective, sure, weapons may feel harder to attain since you can't get them through Valor Points, but, if you could carefully plan item by item when and how you'll get each upgrade, wouldn't that remove that excitement of finally getting the item you've been chasing for so long?
Oh, come on, don't treat blues (nor anyone else working here for that matter) as "Generic Blizzard Employee #7654". That was my opinion. It is what I think, and there's no reason why you should agree with me, that's not only just fine, it's actually good. Disagreement, if constructive, creates discussions, and good discussions are always profitable one way or the other.
Now talking about weapons... how often has it really occurred to any of you that you've never had a weapon drop for an entire tier? Personally I've never been in that position. Have I gotten my weapon late in a tier? Yes. Have I gotten it soon after a tier had launched? Yes. That's RNG. I'd wager if most people could plan their upgrades, weapons might be on the number one spot (depending on the class, of course).
But above all that, the underlying question isn't just convenience, but rather it branches into two things:
-Why do we want to get rid of RNG? Because we can't control drops? Why is that negative if you're having fun playing the game? If someone out there wants to get all the items as soon as possible so he/she can stop playing the game as soon as possible, then maybe the proper question should be... are you having fun in WoW? Because the moment we start thinking on the quickest way to get everything done and then not come back until a new patch has been released might be a sign of needing some time to disconnect from the game.
-Once you control your drops, what's next? removing RNG from quests? from things like which artifact you'll get next on Archaeology or which jewel pattern you'll learn on that next research?
RNG does have a positive aspect of the game. Sure, it makes it unconvenient when we're trying to control everything, but I believe it ultimately falls back to the "having fun" aspect of all this. Would you have fun in a game where you can control everything? For an extended period of time?
No RNG there, but hey, I guess there's a reason companies pay you a pre-determined sum of money each month rather than by handing you an random item you may or may not find use for. I like my job a lot and having a random reward system wouldn't make it more fun.