That's a totally fair question to ask. Here is my take.
To be more specific, nothing in particular outside of gold weapons drops and the fact that run of the mill normal progression items are disguised as "rare" when it shouldn't be.
Problem 1: It's more of the fact that MD says loot is Rare when there is nothing special about it other than it is normal progression, meaning, +1 here are +2 there. Nothing more than that. Since +1 or +2 doesn't really do anything at all in the grand scheme of things, I personally don't feel like its worth my time and or actual $ to reroll. I do have a bunch of the gear, but TBH, the gear and augments they have are the exact same as to what I already have (except +1/+2 better here or there), all wrapped up in a nifty new (and rare) way to get it. So, I have no desire to go for the +1 or +2.
When the great stat squish happened a few years ago, we were essentially told in order to progress the game without too much power creep, there wouldn't be a huge jump in each expansion. Ok, good. Well, that was true for everything since...until MD...where the devs said, "why don't we make this normal progression harder and monetize it". That's the issue. I personally see no issue just skipping this and waiting until it's not a lottery to get stuff.
Problem 2: I have pulled 1 gold weapon out of a few hundred runs, and it's not even something I would use. Now I need 2 to make an undying version. Ok, fine, but why should specific weapons be excluded from runes in a raid? I mean, you can buy undying weapons with runes, but only
certain playstyles get this benefit. If you have xyz weapon type...no no, you need to get lucky to pull 2 items...and the rate at which they drop will take you far far longer than running the raid and accumulating 1250 runes (if you play a class that can use that weapon). This punishes alot of playstyles out there, and is just plain not fun. Now, if I could turn in say 50 fallen weapons for 1 golden age weapon, it completely flips my opinion.
I mean, time is money, and if I can run the raid 15 times on hard and buy a weapon (short list of classes that benefit) which would take, for example, 15x20 mins, or about 5 hours of playing time to do so, why can't I figure out a formula that get's me 2 golden weapons in the same timeframe. I guarantee I have spent 4-5x times as long just getting one gold weapon. What's fun about that? What if I wanted to play a different class and I spent my 2 gold weapons on 1 undying weapon that woops, I can't use anymore. Runes gaurentee a raid weapon...if you are the right build...MD punishes all others that need a different weapon type by making them "get lucky".
Raid = guaranteed item at 1250. Gold Age = no guarantee for similar undying weapon in same timeframe. I believe this is broken. That's just my 2 cents