I guess to make people want to continue in the hypothetical WW for mobile.
more lives after game over require microtransactions being that its a staple of mobile games, and another staple being that you can upload to facebook or something.
As for new things that could pull in mobile gamers i assume they could add WL series minigames to play off of nostalgia, as an alternative mode, maybe add them to standard WW but i don't know. also instead of ten points to win make it only the endless/ score attack mode. Seems to be a theme that works with mobile games
that's all i got.