The problem I have with readying an interrupt is that you are acting before the event that you are triggering from which means you have some sort of sixth sense about what is going to happen.
I might be missing something here but arn't all of your examples actually reactions?
Quote:
Originally Posted by Sadrik Examples: "Freeze we are taking you hostage!"
Trigger: If the goblin takes a hostile action
Power: Magic Missile |
As soon as the goblin makes a hostile action you blast him magic missile, how can you tell he is going to do a hostile action before he does it? This has to be a reaction not an interrupt.
EDIT: actually this is reasonably close to my example where I might allow it Quote:
Originally Posted by Sadrik Fighter holds the line in a hallway
Trigger: If anything comes adjacent to me I attack it
Power: Reaping Strike |
As written this is clearly a reaction. An interrupt happens before the stated trigger action, in this case before the creature stands adjacent to the fighter, which would probably mean that the fighter couldn't attack it!
Quote:
Originally Posted by Sadrik Ranger watches the trenches
Trigger: If that bugger pops up out of cover I shoot him
Power: Twin Strike |
Again this is a reaction to the target popping into view, it isn't an interrupt.
I think you might be in a situation where you are either over thinking the situation or just not fully realising the difference between interrupts and reactions. (
of course I might also be getting the wrong end of the stick and you might have just chosen poor examples 
).
The only example I could see where you might want to apply an interrupt instead of a reaction is:
Fighter stands toe to toe with the enemy unsure of his intentions Trigger: Enemy makes an attack Power: <Fighter attack power> against enemy EDIT: this is reasonably close to your first example.
In the above case I can see an advantage to using an interrupt rather than a reaction because you want to get in the first strike. You obviously already have a higher initiative and have foregone your attack so you are not getting
that much of an undue advantage from this.
I might allow the above case but impose an attack penalty on the action, maybe -2 to attack.
This is theoretical though as it has never come up in my play experience.