Is it possible to add a small delay on creatures, that you teleport to? Like down a ladder, through a portal or would that be a giant pain in the ass. Just enough to give a fair chance of alt clicking and casting a spell/warcry. Opinions?

Maybe the tile you port to stays neutral for that 0.5 second where the player can't be engaged by the AI?

Right now you can time it so that when you grab a portal (or simular), you can cast C2 or warcry right between grabbing and ending in there.
In that way, when timed correctly, you can often launch first c2/warcry.

Fantastic but it shouldn't be just characters post arch. What about low levels when it counts more.

There were some areas like Lab 8 underground that were designed for the NPC to get first strike.
You relied on either resistance or enough AVHP or a buddy close by to be able to beat them.
They are hard if you are not ready or not in a team

There are some areas like later in the Prison where you land on areas that the NPCs can not reach but they can curse and stun the blazes out of you.

Some areas have NPCs that do not attack until you attack them.

We also have the option of landing on NOATTACK squares or NOMOVE squares or other combinations, each of which can have a different outcome and probability of death for the unsuspecting.

These and other variations are options open to the builder of that area to consider for difficulty and balance and are very area specific.

At this stage there is no "delay attack" option other than the tactic that Marky mentioned.

If there is a specific area that is out of balance or too difficult or not operating as intended then we can have a look at it.