It seems, to me, like card sheets are cut in exactly the same order, there is the bare minimum of randomization in boosters. Even opening one box you can already begin to tell the pattern of cards, in other words knowing what card comes next after another one.
I've gotten (of course the worst) one of the retro frame mythics literally back to back as well.
Here is how Set Boosters are structured:
Common slot: Has the EXACT same order of cards each time with the only variation being what your first common is and therefore where you begin in said order.
Uncommon slot: The same issue. The only randomization is where you begin in the uncommon order of cards, although that varies each time obviously.
A special slot: Sometimes you get a borderless card or additional retro frame card. Since it is only one card, naturally it feels fully randomized, although it seems to prioritize borderless lands.
Retro Artifact slot: Explains itself. Sometimes there are two retro artifacts here. (I've had three in a row in about 2-3 boosters in a box) This slot is where I pulled two Sundering Titans back to back. It's shameful that they can't even randomize a slot that has two cards sometimes.
Rare Slot: Self explaining as well. Fully random, given that it's only one card. Although I have experienced up to two duplicate rares in a box, something that had been absent in recent products.
Foil slot: There's one thing to note here besides that this includes on average two foil retro artifacts per box (Mostly one uncommon and one rare). I pulled three Kayla's Reconstructions and two Argoth, Sanctum of Nature here, so either that was, winkwink, very bad luck getting both of these in a box each, or this slot is getting messed with hard this set.
There are of course positives, those mainly being that "The List" slots have a highly increased rate for rares. All the boxes I opened had at least two The List rares/mythics in them. Ephasis on at least.
The special card slot also was, although mainly lands, more than once a borderless card in each box.
In closing, I myself was going to cut back on Magic since the price increase, but the card pool in this set (including retro artifacts) makes this price somewhat reasonable. The quality control issues sour the entire thing again, however. Which is the whole point of me writing this.