Excellent. My favorite implementation of Pong is PLBM Pong from the DOS days: you can make the ball crawl at first and speed up gradually until it's all frantic jiggling of the paddles. Much fun've been had in the two-player mode.
You could in fact do likewise: let the player choose the initial parameters and the speed of change. Maybe with preset difficulty tiers if high scores are kept.
If people are interested in it, I'll try to fix the last few bugs and put it on GitHub. So I'm really interested in your feedback, especially: Would you use a framework like this? And do you see ways to improve the API?
I just started with Phaser last month and it's great. Your tutorials page was a great reference for me(http://www.lessmilk.com/phaser-tutorial/). 2.4 looks great. Have you experimented with the support for boned Creature animations? I've ben testing out Creature for 2D skeletal animation and it seems quite nice.
I wrote an ebook on how to make games in HTML5 with the Phaser framework. It's been out for a month now, and it has made me over $16,000 in sales. I keep making a couple hundred dollars per day with it.
This game was definitely inspired by Flappy Bird, but no I didn't think about that name before today.