Rotation is coming up in April, and most of the good cards in Standard atm will move permanently to Wild. So now you have the choice: Do you want to just commit to Wild and never have to worry about rotation, or go to Standard for a more balanced but monotonous experience?
The best 3 Warlock decks atm are Cubelock (Control Warlock), Evenlock (Handlock), and Zoo. Zoo is pretty cheap and will most likely remain strong after rotation, while Cubelock and Evenlock will be gutted. However, a different version of Control Warlock that uses a lot of the same tools as cubelock is amazing in Wild, so if you want to just play that you'll have a good time. Its called Renolock and its pretty awesome.
I'd look at all the different decks that you can play and consider 4 things: the dust cost, its current viability, how fun it is, and its viability after rotation.