This is probably impossible for us to mod, so its up to you devs
In the patch, can you make the replay engine create a text file alongside the replay file?
The text file would have header info such as the players in the game, the mods active at the time, kill stats.
But most importantly....
CHAT HISTORY with timestamps!!!
Then when you replay, it would automatically show chat AS IT HAPPENS in the game.
Many people have asked for this but I think it could really be possible if you put the info in an external file. That way it doesn't mess up your file format.
Of course this means we should put a UID in the filename now, instead of just "lastgame" as the name. Match the UID between the replay file and the text file and the engine knows which ones go together.
Plus if people want to replay w/o chat - say if someone's being obscene, but its a good replay, they just delete the text file and it replays like normal.