Tekken Revolution has already shown itself as a repository for some of Namco Bandai's more bizarre ideas. A recent poll had players choosing between potential DLC characters like a salmon and a praying mantis. Series producer Katsuhiro Harada says that since this one is less serious and free-to-play, it lets them experiment.
"Because Tekken is a long-running franchise, there are expectations from the players," Harada told Polygon. "This is just an example, if there were a Tekken 7, that would be the next real installment and people would expect the canon story to be continued and tie up loose ends. We would have to have all the characters they expect [in that game]. Throwing in a salmon or alien or something like that might make certain people unhappy. It might not fit into the story. It's been great to be able to try some new things like this."
That's not to say the concerns are all on the fan side, though. Harada said that even the developers expressed worry that Salmon could make it into the game, since implementing the character would have been "quite difficult."