Thanks for the feedback! I'm definitely with you on the feeling of balance. I think it has to do with the winning player not having anything to do wihile they are winning. A friend suggested having the scoring player point the ball for the next round, which I'm experimenting with presently.
I most likely will change the scoring following some other planned changes--as long as it still seems needed. I'm thinking either streaks or more standard tally-up scoring.
Also, yeah, the idea of upgrades is almost a given in a game like this! I am especially interested in the effect of other block shapes on play.
Thanks again for your interest and feedback!