Skills don't need to have interesting tooltips to have interesting uses, though. A 30% healing buff could give you or your cohealer time enough to get in in that extra indirect support cast or two, giving a result that could be just as interesting as, say, a massive 20% haste buff, or as if you were duplicating a portion of your other heals onto the buffed target; the options opened up are about the same.
I didn't say +30% healing potency wouldn't have an interesting use, I said it is a boring use. I 100% agree, having your cast mirrored on someone else or increasing your healing potency on your main heal can be comparable. But one is more interesting and fun to use than the other.

When they gave us the proc crit on heal, it was great. Using that crit proc properly is fun. it feels rewarding to keep the crit and use it right before a big burst on the tank. Effectively this could be replaced by my heal reducing the incoming damage by 5%. The second one would probably mitigate more throughout the course of the fight... but it is dull.

The same is appliable to tanks doing these cooldown rotation. It is effective and strong, I can't argue... but my vision of tanking, beside positionning properly the target, is more than doing a rotation of 5-6 cooldown every 20-30sec while smashing 1-2-3 and holding a weak dot. (I'm not targeting the paladin here... not at all)