I love playing the alchemy market. It's proved profitable for me all expansion long. Part of the reason why its been so profitable is a general alchemy specialization imbalance; almost no one chooses Potion Master on my server. Why? Part of the reason is that a lot of people choose Transmutation Master. The other, more important part of the equation: Few casual players know that specializations even exist.
Come patch 4.3, though, that's about to change -- new alchemy specialization quests are being added in your capital city.