As others have said the healing kit is far too powerful for the amount of damage going out in instances, and as long as fights are scripted even in high end content you will never have to heal constantly and need something to do with downtime.

Honestly I would just get rid of ogcd heals all together and tweak the gcd heals to even it out, you can turn all of those ogcd's into damage and party support abilities to flesh out the toolkit. This would allow you to heal most of the time since you don't have healing bombs anymore while weaving in damage and buffs in between.