A design mockup of it is now available here. When it shows the first page of the menu, select the Action Area page from the 10screens menu in the left side to access that page.

It should illustrate a possible layout of the dynamic actions.

Let me know what you guys think.

I sort of mashed my review of the UI into a single review over here.

Ready for another review round. I have made a detailed description of how I intend the action area to work.
https://docs.google.com/document/d/1rWrcfyA426RsUSkxS85TEXwOM0852iq8AMfH1wMC0Mo/edit
I would like to hear feedback especially about if it seems intuitive and easy to use.

i think it looks good, but i think one thing that could be done on selecting things like onclick and such is a floating on hover tooltip with a brief description of its meaning. but thats just a thought for laterish.

I agree that some tooltips would be good in the final version.

Is OnClick still going to be the only way to activate an item, or will there be ways to activate things simply by meeting some requirement? For example, the auto-accept quests that pop up when you enter some areas? You could do some really interesting things like GHI buffs being added when you approach a shrine, or the screen fading to black when you enter a cave.

The one thing I think might speed things up when creating items (Though it might make it a bit more confusing for new users) would be to rethink the Add Action/Edit Action/Delete Action buttons. Rather than having these buttons at the bottom, what about making the output nodes be the "add action" button, which would automatically attach the new action's input to the output that the action was created from? We've already got little windows for each action, so rather than having edit and delete buttons at the bottom, put them as buttons in the action window. Here is an example of what I'm talking about (Another rough design).

Regarding the tooltips. I agree completely. I have also mentioned it briefly in one of the final steps.

Regarding the several inputs: It is the idea that several start triggers should be supported technically. This is mainly because we will use these Action Trees quite widely in other GH addons, such as GHP. However at the moment I am not sure if we can make other than "OnClick" start triggers, because it might compromise the security. An item that can trigger any script from just doing mouseover could e.g. be very dangerous. Put an infinite loop in one of those and you got an item that will crash your wow without you knowing what did it. It would be awesome if we could trigger scripts when needed, but sadly that is a large security hole. I can imagine that there will be some different input ports that will be relevant in GHP.

Even though we can not support running scripts without clicks, then I have some plans for the attribute system to support some limited scripts, so you can do stuff like consuming items or producing items triggered by some event or condition.

Regarding replacing the add action button. I really like that idea. It will definitively make it a lot easier to use. As you mention the only downside is that it is not as easy or new users. I believe that we can fix that by making the "OnClick" port a bit larger and maybe even add a label in the middle of the edit field saying "Click on the 'OnClick' port to add the first dynamic action".

This is done now