I put up a "blog post with some ideas":http://blog.obsidianportal.com/?p=1330 about how to use the API to make DST creation and editing much easier. It's by no means the one and only way to approach it, just my first thoughts.
I'd love for someone to step up and create an actual desktop application to handle this. If you're interested, please speak up and let's figure out a way to make this happen.
* "The blog post":http://blog.obsidianportal.com/?p=1330
* "The DST API page":http://help.obsidianportal.com/faqs/api/api-dynamic-sheet-templates