Hi Jeremy,
Thank you a lot for your responding and idea about Microsoft Planner.
For this limitation you’ve encountered, I do understand the inconvenience and sorry about it.
Due to this situation, I personally agree that it's inconvenient you can't tag individuals for specific tasks during work. In that case, I sincerely recommend you go to Feedback community to vote this similar feedback: (find out similar feedback, if not provide the feedback forum link (Ideas · Community). Our product team is in charge of the site, and they constantly check customer reviews and feedback, The higher votes, the more attention the related team will pay on. And a lot of the features are developed and improved based on customer feedback.
Please notice and accept my apologies that as moderators in the community, we are not supported for the product design and have limited resources for the advanced info for Microsoft products. To help you send your feedback and requirement to the related development team, we have redirected you to the correct path.
Appreciate for your patience and understanding, and Hopefully Microsoft will make improvement soon.
Hope you having a nice day and really much warm regards to you as well!
Best Regards,
Alina-Le - MSFT | Microsoft Community Support Specialist