Yoshi P, is this what you wanted? (Terra Branford Blues)
Welp, it happened. After 3 weeks, a ballpark 650-700 kills, and 145 Ultros cards, Terra dropped for me tonight.
http://i.imgur.com/ZsZolG4.png
(Only 134 shown since I didn't start keeping my cards until after my first farm session.)
I made many friends, and even some enemies along the way. I mostly stayed patient but sometimes lost my cool. I questioned my sanity, my faith, my life choices, and at one point I even submitted a bug report.
This wasn't a totally new phenomenon. It took me something like 25 windows to catch a Bombardfish of all fishes. I lost 34 Neptos before I finally caught one. Bahamut took me 18 hours of Elmer and one zodiac item took me 42 runs of Stone Vigil.
I know I don't need the card, I just wanted it. But to see a hundred Terras drop in the very same fights I was in, to see person after person join my party to get Terra within a couple kills, it ate away at me. Most people just laughed or cried with me, but some teased and taunted. And what was I getting through all of this? Feeble light and 15 soldiery per kill.
The thing is, I don't believe this should happen. Is this what Yoshi P wants? For some people to suffer while achieving their in-game goals? Nobody should have to play for hundreds of hours to accomplish the very same thing that was accomplished by thousands of others after only a few minutes. This game needs a safety net for their RNG. I wouldn't be mad if I knew Terra had an abysmal drop rate, but she doesn't. I was just abysmally unlucky.
FWIW, in my experience, Terra seemed to be roughly a 5-10% drop rate and Ultros is about 20-25%. The actual chance of not getting her in my first 650 kills at 5% drop rate was 3.3x10^-15, or .0000000000033%.
In conclusion, the horror stories are true, and you don't want to wish them on your worst enemy. If you don't believe it, then it simply hasn't happened to you... yet.
Need a Weighted RNG / Drop System, Please
I completely feel the OP's pain. Pure RNG is just awful. We need a change to the Drop System:
A Weighted Random Number Generator System. A bunch of people brought this up a while ago, when Atma were first introduced (and the % was even lower than today). Specifically:
1. RNG Drop Rate + Increase Percentage(%) Chance for [Item] drop for Every Successful Clear (FATE, Dungeon, etc.), Until it Finally Drops.
For example, let's say the starting Drop Rate is 1% for an Atma. If you do a FATE and nothing drops, Square should add, say, +2% to your chance, so the NEXT FATE you do now has 3% (Base 1%+2%) chance. So at the most, you'd have to do 50 FATEs in the zone (+2% x 50 tries) to finally get your Atma Stone (if you had the worst luck).
This allows Yoshi P to keep that "Random Number Generator" / "Lottery" feel and grind (ugh), while providing a safety (and sanity) net for Players. So if you have bad luck, at least eventually you'll get the Item to drop within a reasonable amount of time. The Actual Bonus Percentage per Win/Clear can be balanced to whatever feels fair (+2%, +5%, etc.).
This Hybrid approach is the best of both worlds. It's frustrating that Yoshi P and the Dev Team refuse to consider something like this; and just stick with a simple, archaic "Pure RNG Only" system (just keep banging your head against the wall, "rolling the dice" and hope one day it drops). It's awful.
Examples like yours of repeating the Ultros fight HUNDREDS of times before you finally got the Terra Triple Triad Card to drop is absurd. Seriously SE?!
This needs to change in 3.0.