I thought about this, and it depends. Having it in teleport means a player can teleport in to a mob or enemy and utilize the power's Untouchable status (which lasts around 5 seconds) to inform them of the potential threat in the area, with added +perception, without experiencing the potential risk of doing just that. On the other hand, Combat Teleport would be the ideal power for the unique +perception proc. The proc activates after the animation/teleport power finishes, so it's usefulness would be best utilized before engaging in combat in order to get the most perception of mobs at a distance. Kind of putting the chicken before the egg... knowing that there is a mob/enemy ahead that is cloaked (thinking Knives of Artemis) means you don't need +perception to see them, but if you've teleported in to an area that looked clear before activating, only to realize that once you've landed there with the +perception activated, it becomes moot anyway. I'll admit this is an outlier scenario for sure, but worth bringing up nonetheless I think.