I suppose it depends on your definition of merge. The function allows you the ability to select a number of channels to merge an external ArtNet source into the console, thereby allowing the external source to control certain parameters of a fixture while the console controls the other parameters.
I would be interested in understanding what other functions you would like within this merge tool. If you have some time, please do drop me an email - chris_ferrante@highend.com, it is always good to have as much input as possible.
With regards the begin and end function in the FX engine, this is not the final pass here and as you correctly point out, there is the need to add extra functionality which is in the pipeline.
