If you want to use runes as traps, I think there are 2 other really nice 4E examples from other classes
The hunter ranger in 4e is a "controller" he gets 2 different traps (which could be rune flavoured) which you could take inspiration in. (One the class got itself the other itw paragon path)
Then for "trapping" objects the Executioner assassin class has poisons they can use for this. Like ones being able to put into a container and when its opened attacks them or others which are over touch.
May not 100% fit but the "trap" just reminded me of this.
The hunter ranger in 4e is a "controller" he gets 2 different traps (which could be rune flavoured) which you could take inspiration in. (One the class got itself the other itw paragon path)
- both can be used with a minor action in combat.
- You choose 1 empty square.
- Enemies do not remark you casting the trap nor remark the square is traped unless they suceed in perception vs your spell DC
- The next time anyone goes onto the square the trap triggers.
- One deals wisdom modifier + 5 damage and roots for 1 turn
- The other one ends movement, forcefully moves the target 4 squares and slows (but no damage)
Then for "trapping" objects the Executioner assassin class has poisons they can use for this. Like ones being able to put into a container and when its opened attacks them or others which are over touch.
May not 100% fit but the "trap" just reminded me of this.

