WOAH . . . no way, I want Tarzan to go to mars . . .and have his own adventure, that has nothing to do with John Carter .. . just tarzan journeying to barsoom, maybe meeting carter, maybe fighting alongside carter . . . but no confrontation between the two, forcing the two main characters to fight in a crossover is a good way to sink it.
though i enjoyed the Dark Horse Tarzan/John Carter team up i did find their reason for conflict to be a bit contrived.