Hi Ryan thanks for posting in the Lucidchart community - apologies for the delayed response! Thank you for your request - we're always looking for ways to improve Lucidchart and your feedback is the best way for us to keep developing a useful and effective product. I've gone ahead and submitted your idea regarding the Actor shape as a participant and support for PlantUML to our product team on your behalf and it will be taken into consideration when prioritizing UML improvements.

For anyone else with a similar request: please submit your feedback using this feature request form in order to voice additional support to our development team. We would also love to hear additional detail about your use case or see an example of what you're hoping to achieve in the thread below. Additionally if you've discovered a workaround to achieve something similar in the meantime we'd love to hear about it! Thanks for your request!