I agree with Katriella’s post - you’re bound to find both serious and not serious roleplay around, especially in the biggest hubs such as Stormwind which attracts a wide range of roleplayers with different roleplay preferences and a large variety of character concepts.
It varies a lot per individual whether they prefer to do longer or shorter /e and /s. Sometimes also the same player might change their approach depending on the situation too (for example in multi player events using shorter emotes to keep up with the flow and pace, and when playing one-on-one approaching the roleplay more as if writing a story chapter with another player).
For the night elf side of things, this thread might be helpful! On top of information aimed at players new to the race there’s also a list of night elf themed guilds. [A-RP] Night Elf Roleplay