While truth is not measured in mass appeal one could definitely try to make a point for this, WoW would win should this be true.
Professional critic reviews indicate that WoW is better, WoW and every single of its expansions scored higher than tera did.
http://www.metacritic.com/search/all...rcraft/results
http://www.metacritic.com/search/all/tera/results
for the rest I really don't know much about tera but trailers so I'll lay off with those type of comparisons. (I suggest you base your counter argument based on this and not on any facts.)