There are several items that appear to have a 1% (or less) drop rate:
Mirror of the Whorl
Nightmare
Enbarr
(other primal mounts)
(probably the weapons from Ramuh, as well)
You could have literally 100s of wins on Leviathan and never see a mirror. You could have similar problems with mounts.
People need real, achievable goals. Planning to defeat Leviathan 1,000 times because it will probably take you that long to see enough mirrors for you to get the winning lot is not a real, achievable goal. This is a punishment you might hand out to yourself.
If the dev team feels level 100 weapons are too good to "just hand out", lock them behind a more difficult fight, not make them a mythical item that never drops. It's really not that hard to get a level 100 weapon from Coil. Which you can then make a level 110 weapon by beating the next turn in Coil. And then you can get a level 115 weapon. Ideally people would be wanting the animus or the tidal weapons to make Coil easier, but honestly it's easier/faster just to get the Coil weapons, which is absolutely ludicrous.
I just want a mirror for my weapon(s) for the vanity skins. I'll want Ramuh weapons for the same reason.
I don't see what it proves, beating primals thousands of times for mounts and low level weapons. I could be the best player ever (I'm not) and I could still never get these weapons or mounts, just because the drop rate is so awful.
I understand the dev team wants to extend the "life" of the game by making stuff take a long time to get, but this is a really poor way to go about it. For "mainstream" and "casual" players, even beating Extreme Primals to begin with is an amazing feat. I regularly watch people wipe Ifrit EX even though it's super easy, much less Titan EX or Levi EX. Are mounts and level 100 weapons only for the "hardcore"? Because really if you legitimately want to get this stuff and not just have it be pure luck if you happen to find a PT that wins and happen to see it drop and happen to win lot, you need you and 7 other people who are SUPER into getting this stuff, and just farm. For days. Weeks. Whatever it takes.
That sounds like a huge waste of time. Just like PvP. No one does PvP for real. Even doing win trades, where you hop in and murder the other PT, then do it again and let them murder you, it takes over 130+ hours to get to rank 40 to even wear the like 3 sets of level 100 PvP gear you bought along the way. Playing legitimately would probably like like 10 times that long, once you factor in waiting for queues, having to actually fight, and like, probably not winning that often. We're talking like half a year of dedicating 8 hours a day to that "super awesome" PvP. Seems good, right?
Almost everything is like that. Animus quest. Novus quest. PvP. Primal mounts/mirrors. Is this content just not meant to be done? It's not like any of that stuff is particularly difficult (except I guess EX primals, if you're not "hardcore"), it just takes forever and isn't fun.
You can try to force people to do really boring stuff and make it take forever, and for a while it might work. Getting people to play your game longer because they have "things to do", but eventually everyone's going to wake up and be like "Ummm. Why am I wasting my life? I'm sick of this. I've beaten Levi EX 567 times, seen mirror like 3 times, and lost lot every time. And a lot of the game is like this. Screw it. I'm out!" Especially after watching someone who dies every time win lot on mirror or something. Or people who just got the achievement, because this is the first time they even beat it. And they did awful. Amazing. I feel so rewarded! Right!?
It's annoying to even get accessories off something like Titan EX using DF or PF, because people are clearly awful and can't dodge mechanics. It took me forever just to get Tremor Earrings. Think I'm going to continue farming just for a stupid yellow horse? I mean, I want that stupid yellow horse, but it's hardly worth the misery. It would take me even longer than getting PvP gear for vanity.