I doubt it
Most of the content they'll add isn't going to substantially change how fun the core gameplay loop is. More characters and more equipment really isn't going to turn this game around. The few gimmicky modes they might add will likely get played for a day and then never be touched again. Golf is the only Mario Sport that I think can substantial improve with updates as new courses add a lot more to golf then a new stadium or gimmick mode does to Tennis or Soccer.
But the core gameplay loop being great is already the common thread in most reviews. So not sure what you are getting at?