How to enhance a Warlock at 11th level?

[Ryujin]

There are definitely some interesting things that you can do once you get into Paragon with a Warlock. Think of what you could do to control movement on the grid with Frost Step and Ethereal Sidestep, for instance. Ethereal Sidestep and the Feytouched Paragon Path is pretty nasty too, as it is with the Long Night Scion PP and Lasting Frost feat. There are a bunch of ways that Ethereal Sidestep can be used to generate automatic damage every round. Toss in Otherwind Stride and once an encounter you can make a real mess of things.