Honestly, voting for Ogre Battle 64 immediately after we just did Mother 3 is a terrible idea. The game is great and I'd recommend it to any fan of SRPGs, but I'm over 25 hours in and the story certainly does not look to be wrapping itself up anytime soon. As with most SRPGs it is one hell of a lengthy game, and compared to others I've played like Fire Emblem and Shining Force, I would say Ogre Battle 64 is significantly more complex, at least when it comes to preparing for a battle. Because there's so much to prepare and doing so can take a significant amount of time, the game feels very slow, slower than your average SRPG, and since story scenes do not necessarily occur at the end of every battle, attempting to play this game with a deadline, even over several weeks, would be a total slog.
My vote goes to Perfect Dark, and one of the things I appreciate most about Goldeneye and Perfect Dark is the way they are designed to be both instantly accessible for quick, arcadey multiplayer sessions, whilst the single player is actually a fair length and with the difficulty levels can be played in depth with a lot of replay value. It seems to me like there'd be a great deal to discuss in an interesting way as there are so many ways of experiencing the game, within both multiplayer and singleplayer modes. In contrast a discussion of Ogre Battle could very easily become bogged down in discussions concerning classes, unit formations etc., which wouldn't make compelling listening for me at any rate.