Dear Elizabeth,
I'm afraid that there is no way displaying the whole comments by default if the comments are long in the Word application. You may need to double-click on the comments to see the full content.
In Word for the web, there is a See more option notifying you whether it is a long comment.
Sorry for the inconvenience.
As our product developers are willing to hear users' feedback on our products, I submit your feedback and convey your suggestions to our new Feedback platform mentioned in the following article for the product developers to know your suggestions and opinions for product improvements.
Introducing Feedback for Microsoft 365 - Microsoft Community Hub
Please note the platform page will be loaded after some time based on the network environments.
You may access the page as follows to submit the feedback as well.
You may use a personal account or a Microsoft 365 business work or school account to submit the feedback.
Thanks for your understanding.
Have a nice day!
Sincerely
Cliff | Microsoft Community Moderator