I do agree in general that some of these things would be nice in ActionScript, but this is an area I can work around, while relevance is something I cannot. The simplicity of ActionScript is part of what makes it work so well, so extending it to add these more complicated things is hard to do well. Also, because you can use relevance substitution in ActionScript, you can achieve many more complicated things using that.
As @rkorinek points out you can do “looping” by having a task that does what you need for a single case and have it reapply. There are other options as well.
I think it is possible to achieve looping or what you need in a generic way that wouldn’t require one offs every time. You can accomplish quite a lot using relevance substitution.
You can use the create file command or download a file with a list of things in it and then do work based upon the contents of that list.