The way I see it, it's not just the unknown of what you're buying with these loot boxes, it's the hideous amount of hours it takes to get such things via progress as well. The two combined are why so many are upset. Hell, if players can get outraged just by people buying scavenger bots for Dead Space 3 in an sp campaign, then they'll sure as hell get ticked off by these methods in a player competitive situation.
The worse parts of it, besides the obvious of addicting kids to gambling, is it's a holiday release title, and there's no real win for the end user. You're either ponying up way more than you should have to in order to stay competitive when the servers are most busy, or lamenting that you're poking along like a snail taking forever to get the gear you need. This game is like the Grinch that stole the gaming customer's Christmas.
And the kicker is, there's no decent sp campaign to fall back on when you're lamenting the mp problems, since it's too short and poorly written. This seems to be botched even worse than the first installment. EA keeps betting they'll have luck rolling the DICE I guess. One has to wonder if they'll be the death of even that dev team eventually.
I want to add a disclaimer that DS3's micro trans was just for comparison, I had no issue with it. I always preferred getting the scav bots at the points you're supposed to, and felt that was plenty adequate. God how I miss Visceral, another great team that fell to EA's greed. I really hope another publisher will buy the rights to DS and keep it going, hopefully with Steve Papoutsis as studio lead, now that he's free of EA. It would also be justification if Steve names his team Vengeance.