There was an old joke among myself and some of my friends playing World of Warcraft about how it was convenient that bosses are all big so you can see them through the spell effects. Of course, there’s some truth to that. Even in a dungeon, it’s easy to lose sight of a boss under the effects of a few people hitting the same target; in content with large groups, you can often lose sight of the boss completely beneath an explosion of special effects.
It’s neat to have effects to go along with your abilities, of course; seeing the flare of something happening to your targets is part of how you know you’re doing something. But City of Heroes in particular had people claiming they couldn’t even see what was happening half of the time, and there are certain bosses in Final Fantasy XIV with facing-reliant attacks where it’s hard to not just pray you’re avoiding where the blob of spell effects is facing. What do you think? Do MMOs go overboard with particle effects?