Back in the day, Instant Healing used to be a toggle power for regen scrappers/stalkers/brutes. Since then, it was turned into a click power with a 10 minute cooldown. I would love to see this power turned into a toggle again to make regen builds more viable. Even if the cooldown was reduced at least by half, that'd be a vast improvement. I just don't feel like this power currently holds a candle to comparable powers like "Rise to the Challenge" in the Willpower set.
Maybe I'm just bad at gearing my regen brute (he's only level 32 with no IOs) but I die quite frequently, even with Instant Healing active, so it doesn't exactly seem game breaking to have it on all the time; spike damage will still get me killed.