I think the basic argument Syp made is that side quests distract him from the main story, so he would prefer to eliminate them and boost the experience gained from the main story.
I can understand that perspective. I’ve forgotten what’s going on in the main story of MMORPGs plenty of times. (In those cases I might argue that the main story isn’t worth remembering, though.) Syp didn’t mention which games were problematic for him, but I’ve had trouble keeping up with the main story in the later expansions of Rift and of course WoW, in which I never have a single clue what is happening story-wise. ESO used to have a main story issue, at least prior to One Tamriel, when you could only do one piece every 5 levels.
I don’t have a strong opinion about this, to be honest. I don’t have a problem with either option, or even a game with no quests. It depends on the game. I’m pretty sure some games I only consume the main story (FFXIV and SWTOR) and other games I consume the main story plus side quests (WoW and Rift and LotRO). It just depends on my mood at the time, and whether I need the experience points, and how much free time I have at my disposal, and how the game is structured.
I can’t recall any game in which I’ve actively been annoyed to have to do side quests. Sometimes it’s disappointing to have to stop the MSQ in FFXIV to level up before proceeding, but it doesn’t anger me. It’s more like a commercial break. I might even be able to make an argument that it builds some tension, story-wise.
For another perspective, in LotRO, for the longest time, I only played side quests and never did any of the main story. I always found the side quests there plenty interesting and engaging, at least in terms of quest text. (Your actual game task is almost always to go out and kill 10 rats.) It’s only recently that I’ve gone back and tried (fruitlessly) to catch up with the main story. (In the old days, you couldn’t do the epic story without a group.)
If you’re the type of person who feels compelled to complete every quest in sight before moving on, then I could understand why excessive side quests would get old. There was a time when I did that (in Rift or WoW, for example), but FFXIV taught me to minimize the quests I complete in order to hit my leveling goals, and leave the rest alone. These days I have no problem looking at a map full of pending quest icons.
I guess I approach questing differently in different MMORPGs. My main goal in any MMORPG is usually to experience the journey of building up my character from a simple farm hand to an all-powerful slayer of dragons (ie. to level from 1 to the maximum). I don’t necessarily come to an MMORPG to consume a story. (In the old days, there was no story to consume.)
It’s usually the mechanics of an MMORPG that draws me to it more than story or setting. The feel of the combat, the pace of progression, the freshness of the loot drops, the ease of inventory management, the variety of things to do, stuff like that.
I suppose in the end I would have to land on the pro-side quest camp because if an MMORPG has nothing but a main story quest path, it’s essentially a single-player RPG where you play it, then put the game away, never to return. There are MMORPGs like that which I’ve enjoyed (SWTOR, Neverwinter), but overall I don’t think that’s healthy for the genre, which needs to build games that you can come back to again and again.
Now that I think about it, in a perfect world, MMORPGs should have multiple main story quests. Or, if you like, multiple lengthy, meaningful side quest chains instead of one-off “kill 10 rats” affairs. To invoke FFXIV again, there is a thing called the Hildebrandt quest which is a long chain of quests that follows the misadventures of a wacky inspector, and has nothing whatsoever to do with anything, as far as I can tell. There should be more of that kind of thing in MMORPGs.