|Back in Pandaria fishing|
Even though I don't play that often, I have Grand Masters in every profession except Leatherworking and Skinning. The crafts for my main character, Herbalism, Alchemy, Cooking, and Fishing, will probably be max level again once I focus on him.
For some people, this would be total waste of time. Even though there is little challenge in crafting in World of Warcraft, I find it to a lot of fun to plan out the leveling and be able to produce what I need myself. To me, and, I believe to many, there is great value in offering a variety of activities in a MMO. Spinks discussed this at length is his recent post.
Even when playing infrequently it is nice to be able to do different things. For me, I alternate quests and crafting. Sometimes I want to level, sometimes I want to complete things, sometimes I just want a distraction. When I played more, I played through dungeons and even did raids one night a week with my guild. Playing different classes provides variety as well.
Most MMOs today are generalists. Keen suggested that more MMO games need to focus on what they can do that other games can't, I suspect he is correct. World of Tanks is a great example although others wouldn't consider it an MMO. However, for me, I love fantasy games and I love being able to switch between different tasks I enjoy as I like, so I'll probably be playing generalist games, and, as long as I'm playing one night a week, only one at a time.
Oh, as a side note, Mists finally went on sale so now I'm able to fish and farm again and improve my skills while doing it.