The addition of power cooldown number overlays is definitely one of the best modifications done to the code to date, hands down.
Frankly, while I would kill to have HeroStats back, the big reasons were less about power cooldowns themselves and more buff timers and xp/inf rate calcs. While I bet the xp/inf rate calcs could be integrated fairly easily into the game, I'm not sure how one would integrate applied buff timers to be remotely as clear as HeroStats could make it. When it comes down to it, a big ol' block that changes color over time and has the countdown to expiration on it beats out the small dots that are teammate buffs, and to rework that would likely take a lot more than the patch to add numbers to power cooldowns was.
I sure hope someone can pick up the mantle and continue the modifications necessary, though. :)