Rich content is better than raw size.

I'll compare three Elder Scrolls games: Morrowind, Oblivion, and Skyrim.

Oblivion had a really large world, but a lot of it felt rather bland and samey - all the dungeons started to blur together after a while. Skyrim's world is the same size of smaller, but the dungeons have a lot of detail, each one is unique, which is really important because dungeon crawling is a big part of Elder Scrolls games.

Morrowind was bigger in raw size, and it had a lot of content, but a lot of the world was empty wastelands and a lot of the people were unimportant information kiosks.