Got a grav/kin controller who has been carrying around wormhole for a few levels, and I'm still not sure what the best use of it is. I got it because the idea of the power itself is great, but how to best use it in combat?
Two things I like to use it for are corner pulls and dropping a second group into aoe range.
Corner pulls involve using wormhole to drop the mob in a corner, eliminating it's kb effect. Sometimes this can be done from a safe place to virtually eliminate their alpha strike.
Dropping another group in range is where I utilize it most. In crowded areas the meatshield will aggro a mob, I'll wormhole the nearby mob into the middle of our combat area to maximize the aoe's. I find it fun when teamates look for that other mob before realizing they've already killed it. Of course this tactic comes with risk...
I'm sure others have different strategies.
Don't forget about the stun effect of the wormhole, it's a pretty good AoE stun power, I often use it on a group that I'll teleport to the exact same spot they are to begin with, but yeah I think I've used it the most to bring more meat to the tank and AoE dmg dealer on the team lol.
I have to share my favorite use of the wormhole corner pull.
In a duo with Captain Spud playing his grav/? controller and myself with my storm/elec defender we were able to tear through +4 and +5s using wormhole. Essentially spud would let me know where he was pulling to and I would start my Freezing Rain just as he was pulling. Then it was just a few AoE blasts from total destruction. This would work well with a dark/* defender's tarpatch as well. Even better a */cold, */storm, or */dark corrupter to make it even easier.