I'd go for Warp In The Weave
This power has another use that many are missing. It can save an ally whose square you're standing on. Normally you cant stay on an ally's square, but if the ally is unconcious, you can. This means that you can save a dying ally from a dargerous AOE spell.
Awesome avatar created by Ceika!!!! Thank you.
I choose Shield on level 6 - because itīs not for one attackig monster and not for one attack and Iīm defender and this utillity gives me +4 to AC and Ref till the end of my next turn (and this I can use for negating monster opportunity attacks).
And at epic levels - where my AC and Ref will be above 50+ (AC = 54...) I maybe switch "Shield" for "Warp in the Weave"...
Since Warp In the Weave removes you as a target of the triggering attack, it's incredible for non-immediate-action-based-defenders (auras, paladins), since it lets them punish the attacker in addition to negating the attack on themselves.
As a swordmage, I may try to avoid immediate action utilities, since aegis or dimensional vortex are almost always better, but if your DM tends to respect your mark, ways to negate/mitigate/punish attacks on yourself become much more valuable.
Ah I foud arcane 6 utility "Peer through the Void" - encounter stance, gives me additional sence and this is Blindsight? And blindsight doesnt need Line of sight, but line of effect. I donť need torch anymore, I dont anymore aware of hidden or invisible enemy. And with Masters blade, which gives me +1 to attack rolls with basic and at-will attacks - this is awsome, better than Shield.
That's way too situational to use an utility slot on. Note that area effects (which you should have as a swordmage) already ignore concealment.
Yes, this is truth - in general. I have many powers (include one at-will) with area effect, but I grant CA to hidden or invisible enemy. And -2 to all defences doesnt sound much defendery.
Its "encounter" stance - and with masters blade I can have +1 to basic (opportunity) and At-will attacks each encounter.
I forgot to wrote, that we are in campaign with many damned tieflings warlocks, and they are hidden...