Amongst the basic things that you should expect from a good embeddable BPM solution include scalable and reliable architecture, and the ability of quick integration (this could be across different platforms such as MOSS 2007, Microsoft SharePoint, BizTalk Server, etc). Also, your embeddable BPM solution should incorporate as many BPM functions as required, while also leaving room for high levels of flexibility though the use of a standard based approach.
Further, the use of an XML variable interface can help simplify the input of XML data into the workflow, and the same also holds true for creating new XML schemas or simply importing ones that already exist.
A good embeddable BPM solution should allow interface access through various channels, and should be able to define various media types when it comes to the delivery of tasks (these would include web, email, voice, SMS, IM, etc).
Overall, your embeddable solution should aim at increasing your visibility through the use of a simple to use set of features which are run on the latest technology, while also being able to seamlessly integrate with your business’ existing infrastructure; and at all times, paying due attention to 3rd party software usage restrictions.