Any suggestions on a good next step after sand sprites? I tried Theren's vines/creepers but they are flat out brutal.

>I tried Theren's vines/creepers but they are flat out brutal.

I found they start getting less brutal with around 90ish ranks, and once they do they train absolutely great. If you're still around Theren, you might want to try to pick up some more ranks in blood wolves if it's not full; they should be able to patch you over.

I went straight from capping sprites to silver leucros a bit further north. May be a bit of a step, but you should be able to do with with buffs.