This project will allow you to view previous Hangout messages on your Android Wear device. It requires root and sqlite on your phone as well as autowear, autovoice, and autocontacts. Make sure to have the variable $SQLITE3 set to your sqlite3 location on your phone (if you have Titanium Backup installed, you can set %SQLITE3 to /data/data/com.keramidas.TitaniumBackup/files/sqlite3). You also need to make sure that the sqlite3 statements (in task Name Picker and View Hangouts) are accessing your hangouts database. On my phone, this database is located at /data/data/com.google.talk/databases/babel1.db.
There are two ways to view messages. First, you can say "view messages from XXXXX" (using autowear listening). This will show you a list with previous messages from XXXXX. The second way is to run the 'Name Picker' task, which will give you a list of your previous hangouts contacts to pick from. Once the message screen pops up, you can tap a message from the list to view the full message (if it was too long) or you can long tap any message to reply by voice.
I hope everything works for you. If you need help, let me know. Also, please post any changes or enhancements that you make.