X per fight is kinda pointless, it already has a cooldown. Why does it have a cooldown if it is gonna be one per "in combat" instance? 3 per fight is doable, that's probably more than enough.
Healing throughput is getting nerfed for BH/T. Healing cast speed is nerfed for Sage and Sorc. Truth is, now people will sit at 20% HP praying for a heal and getting themselves killed because they don't want to use a medpack. As a DPS, do you stare at the HP bars of all raid members? If you're sitting at 15% holding off on using your medpack, do you stop and consider that the tank is also getting channel healed because of a particularly rough series of boss moves which will kill them without focused heals?
How many times have you heard on voice chat during raids that some DPS needs a heal bad, but you simply cant throw one to them because of some other thing going on across the arena on the tank? Healers have to consider the situation on the ground at all times. Keeping the other healer alive and the tank takes priority.
Honestly, players, especially DPS, will be saving that medpack for when the healer is dead, and trusting that they'll be healed when in fact, too much is going on to make that happen. It adds a randomness to encounters that fall outside of the realm of skill. I don't really care that i get my free instant heal via medpack on CD. What i really care about is that people will not use them when they need to, leading to wipes on encounters that involve traps and knockbacks, and not meeting an enrage timer because one DPS was unlucky.