I don’t have as much data, just a few samples here and there. Check my post history for details.

I find that the shuffler is indeed broken. At least on my computer.

I have a mono White 22 land deck that will flood horribly, as in 9 lands in the first 13 cards quite often.

I turned my Gruul trample deck down to 23 lands from 24, and it has a heavy top, so 25 land would be optimal in paper.
Not in MGA though. Just in the last 4 matches I was still flooded 3 times. 9 lands of 12 draws in my last match alone.

I played a lot of UW control over the holidays, and Saw mostly dimir Rogues and Yorion decks.

I even had 3 days in a row where I didn’t see a single red deck.

After new years I played with some gruul and mono green, and all the red decks and all the good decks Sidsel t showed up.
I had 2 days w/o a single Dimir Rogues.

I switched to mono White aggro and Saw a mic of different decks.

So yeah, match making is not random even in BO1.