Change the rendered output of a Message entity
See the Messaging documentation, specifically this overview on new features. You likely want to override the tokens provided using a callback which is supported by the module:


  Callbacks: sometimes we can’t use the token system, for example if we
  need to show different results based on the value of _two different
  fields. This is an advanced feature, which is meant for developers,
  and is documented in the module.


I've not done this myself yet, but I've used the Message module and Views -- digging through the module and documentation should get you there now that you know it's possible.

From the message_example README it sounds like you want an activity stream:


  The UAS (User activity stream) view is dependent on Panels, as it uses
  "Panel fields" as a row plugin, along with the Message's partials.


Which you should be able to look at for inspiration in the example module.