I enjoy some multiplayer games, and even absolutely adore some of them. There are games whose entire design derives from the human interaction. For a simple(ish) gameplay where the human component makes everything, take Planetside 2. The engine is a bit clunky, the gunplay is ok but not the best either, and the premise is terribly nonsensical. Yet, nothing from that matters as it's all about what happens when a hundred players take part in a coordinated combined arms operation across a giant map, organised across multiple platoons. The player organisation allows the simple game mechanics to be used as force multipliers, and it's beautiful to see things happen, squads synchronise their pushes, platoons joining up, reinforcements rerouting... Some of my best ever multiplayer time was in that game, which, by all accounts, has some serious design and technical issues. But from the ground up, it was built for human players, including leadership structures, communication channels, shared map markers, beacons, smoke markers, transport vehicles, etc. And that makes it good. Replace the players with NPCs and all you have all of a sudden is a below-average FPS with large maps.
Same goes for mmos and faction vs faction (or better: faction vs faction vs faction) pvp areas. Whether it's Lord of the Rings Online in the Ettenmoors or Guild Wars 2 (for the two I'm the most familiar with), I love what comes out of large amounts of players coordinating against an opposition doing the same. The individuals melt away, and as influential as a few good players can be, the greater part of success comes from team effort. This, to me, is what good multiplayer design is all about.
The flip side of the coin though, is when multiplayer is just an additional feature, and here the results vary. On the brilliant results side, there's ArmA3 or DCS for example, epic sandboxes in the first place, to which multiplayer adds another purely additional layer. On the less stellar results, there's pretty much every modern mmo, where every game universe gets reduced to the lowest common denominator with stupid names, bunny hopping half-naked people or eyesorely bright dressed up clowns spamming emotes. To each their own, but I play a lot for escapism, and sadly, it doesn't take much to break immersion. And while NPCs can be dull, at least they tend to fit in the virtual universe they're part of. Humans often will, but the few that won't will easily dispel the illusion.
And it goes beyond the stupid, it goes to the internal consistency of those virtual universes. Take ED and the suicidewinder as a case in point. This is a universe where, apparently, random people suicide aboard their ship with no consequence to themselves apart from the inconvenience of either dying and errr, dunno, respawning maybe, or being magically ejected and returned to the nearest station. No police investigation. No insurance scam enquiry. Nothing. Now, have I ever been bothered by suicidewinders on a gameplay/progress level? No. Because I know how to respect speed limits, watch around me, and well, I've got cash on hand if needed. But every station approach in Open where I adjust my behaviour to the possibility of a suicidewinder is an instant reminder that I'm sitting at home, playing a game whose universe makes no sense. And while in Planetside 2, the universe doesn't matter to me, in ED, it's pretty much the whole point, and multiplayer ruins it.
Basically, the idea of multiplayer is great. It's something I used to dream about, and when Meridian 59 and Ultima Online appeared, it was like dreams come true. But those dreams soon faced the reality, and the reality is that due to ourselves (the gamers) and the gaming industry being exactly that (an industry), we can't have nice things. This became terribly obvious when UO adapted to the reality and killed the dream: PvP got killed with "PvE" servers, and PvE took a kick in the balls with core player agency being taken away (food, a key part of player economy). This was to quickly become the template for large multiplayer games: sanitised PvP and dramatic lack of player agency. There are exceptions (EVE probably the main one), but overall, the reality of multiplayer is that it doesn't take that many players to disrupt a game through clever use of in-built mechanics, and fencing everything off is cheaper than designing a game around that possibility.
And past that, there's also the inherent constraints that multiplayer as a feature brings on a game's design. The restriction or complete absence of moddability, since it could interfere with a) the Holy Balance (tm) and b) the low effort cosmetic cash shop. With mods gone, so is the possibility to tune/enrich the game to your liking. Gone is the implementation of (some of) your dreams in game. You're back to pretending some more in front of your screen. And with balance, gone is any permanence in what you enjoy as it might be modified or deleted from the game because someone, somewhere, found a way to use it in a way that displeases the developers or the community. And so is a big part of variety as it's less effort to tune percentage decimals than to have asymmetrical stuff all around. Take the old Master of Magic game (a fantasy 4x, probably the first in the genre but I might be wrong). One of the many things it had for itself was a glorious disregard for balance. It was choke full of overpowered races, units, spells and heroes. And that was half the charm: the power trip it gave you, no matter how you chose to abuse it. And not abusing it was another option, challenging yourself if you so wished. Modern 4X games, by comparison, most of them multiplayer, are often incredibly bland, resorting to the percentage decimal school of faction design. Because imbalanced multiplayer would require restraint from the gaming community, and as Ultima Online demonstrated ages ago: it's not going to happen.
And then there are other direct gameplay decisions instantly forced by multiplayer. ED being multiplayer instantly means speed limits in space. It also means instant travel. And we're back to escapism. This is a universe where one can fly to the centre of the galaxy quicker than in takes to fly from Dublin to San Diego. I can fly from a system currently suffering from a mass famine state to one full of food supplies in less time than I'd need to drive to the corner store in real life. So, why are they hungry again? Is it just me carrying stuff around for mankind? And why is the galaxy so empty and unexplored? Why is "Colonia" the only place where people decided to settle? Take Frontier (Elite 2) or First Encounters (Elite 3). Hyperjumps are instants as perceived by the player, but the in-game clock boosts forward massively. And suddenly traveling around the place isn't instant anymore. Neither is in-system travel (time compression vs supercruise). I know, many won't care, and when I play an arcade shooter like Everspace for example, neither do I. But I expected more from Elite. Since FE2 with its newtoniam flight, time compression and Milky Way based universe, it felt closer to home. Something that felt more believable than, say, the world of Privateer (to whom I lost many many hours of quality entertainment nonetheless). And the second multiplayer became a native feature, that was gone, and it's back to pretending harder.
This is not what I want. I spent enough hundred of hours around a table playing pen and paper RPGs to know how to pretend. This is, btw, a great experience I recommend to everyone. But with the technological leaps we've made, while some degree of pretending will always be involved, I should have way more tools and options available to me to do things in a more believable universe. Multiplayer however, gets in the way, and for both social and technical reasons, often ruins the kind of games I always dreamed of.
So, to conclude, while I certainly appreciate the social aspect and in some cases the magnificent gameplay benefits of multiplayer, single player games are by far my preferred kind of digital entertainment.
