I'm very new to vCO but have done a lot of automation using powershell. One thing I miss -a lot- is the ability to play around with objects and code in an interactive shell.
By contrast, testing what an object looks like from inside the vCO editor is a lot more difficult, since you have to write at least the rudimentary flow of your action and then call on it from a worflow, before you even get to execute your code. Then you need to add tons of System.log statements if you do not know the attributes and methods in an object, etc.
But of course, there are several javascript-shells out there and maybe it wouldn't be too hard to set up an environment similar to inside a vCO workflow, so you can call on the same javascript modules for instance?
Basically a less time-consuming way to develop and test code for a non-javascript programmer would be very useful.