Generally yeah. Also the concept of these Daily and/or Weekly achievements scaling with guild activity would mean smaller guilds can participate. It also allows the achievements to scale with the game's playerbase.
I honestly don't see how guilds could be a bad thing. When I first started playing Poxnora, it was my guildies that helped me and taught me how to play Poxnora. Nobody is forcing you to join an "elite" guild. I join a guild that my friends are in. That's all you have to do.
Something that could be played with for a Guild Tournament that could be directly integrated into the game infrastructure and wouldn't give larger guilds the upper hand would be a system where guilds nominate certain representatives to form a team and play against the other guilds' teams.