To my knowledge, unlike sliding, teleportation occurs in 3 dimensions, i.e. can be used vertically. This may change damage calculations.
I am converting my 11th level 3.X rogue/psion/shadowmind/samurai to 4.0 and am needless to say finding it very difficult. The best thematic class for my character is definately warlock, but mechanically there is no good way to convert him. Regardless, I am opting for the feylock and I am somewhat surprised by the criticism the locks are receiving.
I have been pouring through threads trying to get a feel of how to tactically and strategically synergize powers both with each other and with my comrades. The most obvious difference between the warlock and the other classes is that the utility of warlock powers is far more case sensitive and therefore far more complex than the other two strikers. However, hypothetically I find that just because warlock's powers are situationally conditional, does not translate to them being limited. Rather, they must be used in different ways in different situations.
Here is my build (and I'll follow with tactics):
Human, 11th level warlock, fey pact, feytouched paragon
Str 13, Dex 14, Con 16, Int 18, Wis 12, Chr 22
Special: +2 Chr, extra skill, extra feat, extra at-will power, human defense bonus, misty step, prime shot, shadow walk, feytouched action, slashing wake
Powers:
At-Will: eldrich blast, eyebite, warlock's curse, hellish rebuke
Encounter: Witchfire, otherwind stride, mire of the mind, will of the feywild, hunter's quarry
Daily: armor of agathys, hunger of hadar, summons of khirad
Utility: ethereal stride, feyswitch, warlock's stride
Feats: blade opportunity, weapon proficiency: bastard sword, quickdraw, darkfury, Warrior of the wild, improved misty step, action surge, twofold curse
Trained Skills: arcana, bluff, diplomacy, history, insight, stealth
Pertinent Equipment: dragonslayer bastard sword +2, pactblade +2, boots of springing and striding
Tactics:
Attacked by group of arial enemies:
1st round: curse two targets, hunter's quarry most powerful target, use Armor of Agathys.
2nd round: curse two of the flying targets, cast hunger of hadar below group of arial enemies, use ethereal stride or warlock's step to teleport to adjacent square to flying enemies, use action point and otherwind stride to immobilize foes and then teleport back down to the ground to safety immediately next to hunger of hadar.
3rd round: curse two more targets, use misty step if available to teleport to other side of hunger of hadar, use will of feywild to teleport ground foe above hunger of hadar (and optimally adjacent to aerial foe and directly above prone immobilized foe below).
Here is how the damage works out: beginning on the 2nd round, otherwind stride deals 1d8+8+(2d6 to cursed targets)+(2d6 to hunter's quarry) (which is incidentally at +7 on top of normal to hit bonuses because of action surge and feytouched action), teleporting away causes 4, immobilization causes flying targets to fall for 1d10 dmg/10' fallen and land prone, beginning their turns in hunger of hadar causes 2d10+4 and 1d6+7 to targets adjacent to me. Targets are immobilized and prone during their turn so just assume its my turn again. Cursing two more targets and sustaining the Hunger of Hadar will allow secondary attacks that cause 1d6+7+(2d6 to cursed targets). Because all enemies are blinded, I can stealth and with all the movement I have concealment. The will of the feywild would teleport another target above the hunger of hadar dealing 2d8+10 dmg +2d6 for cursing on top of dealing the 3d10 for falling damage and the same damage to whomever the ground foe falls on top of. Misty stepping will cause 4 damage and Armor of Agathys will cause 1d6+3. On the enemies turns, they are all prone and blind meaning they have to spend their entire turn just to get up and exit the zone of darkness. On top of that, for each enemy that moves by me, I'll get an OA which I can take by quickdrawing the bastard sword which is another 1d10+3.
Presuming everything works and a height of 30', here are the actual numbers before the beginning of my next turn:
Cursed hunter's quarry: 134.5
Cursed targets: 120.5
Ground target: 76.5
Divided over the several rounds, this is not such impressive damage compared to a rogue with combat advantage, for example. However, consider that these enemies are effectively out of the fight for the rounds in which they are accruing this damage and that significant battlefield control is occurring.