Problem with this is that melee damage does nothing special. If DD are hiding behind ifrit, it's from the 1.2k dmg incinerate, not the 700 dmg swipe. The highest damaging physical ability that can I can think of right now comes from Ureaus's body slam (1.7k to a drg), and thats a huge aoe (which also by your description I take wouldn't be covered at all damage wise) this buff would be utterly pointless. It'd make strongholds easier (as if they need to be) that's about it. No one's gonna stand in front of chimera, no one will stand in front of miser and ifrit. The idea is good, but it would literally have no use.