Yeah, I actually recheck it on live right now on myself and it's working like it use to (pre-nerf). I do remember it being super awful at some point between 5.0 and now so yeah... not sure what to think now. Most of the time it did massive overhealing anyway in pve. But I remember lots of complaints about the ability in pvp so blizzard actually buffing it makes little sense.
I've tested it, and it still copies the full amount to the heal target (luckily).
Personally, I quite like to use it when the shit hits the fan, or when excessive tank healing is required. I still think the cooldown should be shorter though, but I suppose that won't happen. It's not the best cooldown in the game, but at times I'm surely grateful for it. :P
Yeah Guardian for holy is just the same, and even better with the haste bonus.
I think it is one of the best CD in terms of tank-healing. Yes it is very situational, so 5min CD is not a problem since you rarely use it twice to its fullest in short fights (5-7min are short fights). But being able to tell your healing mate "go frenzy on the raid, I take care of the tank(s)" during burst AOE damage and a raid spread everywhere, it's just very nice to fully restore your tank in 1GCD, 2 if really hard damages.
Well, the talent change trick was stealth-fixed (in a stupidest way possible) rather quickly.
Talent change trick is pretty easy to change and fix. The gear swap they could make it if you swap gear the buff disappears that is all they could do. But they could have done that ages ago so it still begs to question will they fix it? Unlikely.