Include Subject / Title in Custom View filter properties

It’s very helpful being able to create Custom Views in an Inbox.

However I would like to be able to create Views for my client where a certain phrase or word is included in the Conversation Subject/Title or body. Currently this isn’t possible.

Please can we add some more key fields like this so that we can create Custom Views that include conversations pertaining to a specific topic.

This is so needed to really be able to set up the inbox properly.