User blog comment:Alemas2005/Community Vote on Emotes/@comment-5671588-20140428181250/@comment-1693968-20140428181907

There are actual downsides to having too many emotes. One of the largest reasons is that we have no list of emotes elsewhere. When people want to see a list of emotes, they go to MediaWiki:Emoticons, and the list is excessively long. If there's emotes there that never get used, they might as well be removed, since it only makes things less organized.

There's also the technical aspect of it. Too many emotes increase load time and lag. Albeit a single emote couldn't increase it enough to even be noticeable, an extremely large group could potentially hurt the load times. Every time a message is posted, the server has to cycle through the entire list, and replace the text with the emote. This takes a minimal amount of time, but as the size of the list increases, the time becomes larger.