i dunno about other DW games, but 7XL adds 3 new characters for wei (well, two new ones and Pang De, who was in 5) and Legend Mode, which is a bunch of stages built around characters that didn't get any screen time in the original game's story mode and a bunch of updated versions of stages from older games.
They add a bunch of new weapon styles in as well, giving Zhao Yun, Xiahou Dun, Guan Yu, and Zhang Fei brand new weapons.
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