@nickwild I had a thought today that gives you another option, a little different to what you first suggested, but perhaps a little easier to use?
If you download the workflow from the same link above, it should now be at version 1.1.0, and include an additional flow.
With this one, open Alfred, type dntd followed by a space and then the content for your new draft. Press return and then you should be presented with the Alfred input dialog window again, this time for tag entry. Enter your comma-separated list of tags, and on pressing return, a new draft will be created.
There is no need to remember a splitter string for using this one, the return key does the splitting, and unless you modified the splitter to be a single character and ignore the (optional) spaces around it, it should be fewer key presses to run through, so fractionally faster. But I think the not having to remember the splitter string is what swings it for me - if yoiu are not using it all the time, it would be easy to forget.
Hope that helps.