I missed this last week, but Drafts has been updated with a useful Workflow integration to easily create actions that can trigger workflows with text. From the Agile Tortoise blog:
Drafts 4.1.2 has added a new “Run Workflow” action step to provide integration with Workflow app from Desk Connect. This step makes it easy to fire an workflow in Workflow app with a single tap. The action step can be configured with the name of a workflow, has a template to construct the text sent to the workflow and optional flag for whether to return to Drafts after execution. Under the hood, Drafts is constructing x-callback-url URLs to trigger the workflow, but this makes it much easier for the novice user than constructing them yourself in Open URL action steps.
Similarly, the latest version of Workflow has added a shortcut to create a Drafts action:
As an added bonus, the latest update of Workflow has added an option, when viewing settings on a workflow, to “Add to Drafts”, which will open Drafts and automatically create an action, setup with a “Run Workflow” action step, ready to go. This feature will be rolling out over the course of the next couple of days, so if you do not see it immediately in Workflow, try again later. For more details, read the Run Workflow action step documentation.
I'm using this to quickly send links copied from Twitter (which still doesn't support the iOS 8 share sheet) to Workflow via Drafts, and it works well.