As long as the concept of microtransactions doesn’t limit me from earning anything that’s in the game. I don’t really mind. I like that they exist for the people who want to play something, but may not have the ability to invest 100’s of hours into in order to fully enjoy a game. It all boils down to how they’re implemented, and are only really a problem when a game becomes too dependent on them or tries to constantly force the player to acquire them.
This is practically an article of its own, mostly because there are so many factors at play. Loot boxes are great. They are fun and there's a certain rush from opening one or two or 20. But poor implementation can shed a bad light on them. My number one thing is that they have to be earnable in-game. Loot box microtransactions are awful if developers don't offer the same opportunity to players who don't pay money. If the field is balanced, then I'm all for them, microtransactions and all.
Let's say I don't have a chance to play an Overwatch event, but really wanted a shot at the event skins. I've got no problem dropping some money for the chance, because I know I'll be grinding out and playing for other event skins later. Loot boxes are most often in games I find myself pouring hundreds of hours into, so the occasional microtransaction to support the dev that gave me hundreds of hours of enjoyment is fine by me. In many ways, purchasing microtransactions like loot boxes is my way of tipping the developer for an exceptional job and an enjoyable experience.
I don't like the general idea of loot boxes, outside of a cosmetics thing. I don't hate microtransactions in general mind you--stuff like season passes and other DLC are fine as long as they're reasonably priced. But paying for the chance to hopefully get something useful to you, I feel is a rather scummy practice, especially when real money is introduced into the economy. It's a thing that can easily trigger the same tendencies as you would in a gambling addict, and without proper ways to limit spending on the loot boxes, that's really... well, just pretty terrible. It seems even worse in games you have to buy in the first place like Shadow of War, because it's just tacking on extra money given to Warner Bros that may or may not be worth the money you spend.
If you have the option to buy individual items alongside or in lieu of earning (or buying) loot boxes, then okay, whatever. But paying for just a chance of getting the thing you really want is, by definition, gambling. Some people have personalities and brain wiring that won't be affected by the setup, while others can and will be open for exploitation. It's in general a shitty practice. I say this even though I love Overwatch.
Honestly, I don't remember the last time I played a game that involves loot boxes. I mean, I'm not a multiplayer person and I'm not exactly competitive so I'm probably not the best person to answer this question. However, I can say that as long as the core game isn't impacted by the loot boxes, they're fine. The practice only becomes bothersome when people are roped into spending money and gain an advantage based on that.