If as a bard with so little to normally have to worry about you can't manage to watch your healer's MP... then why should they bother to watch your HP? As a healer I absolutely hate it when I have to shout for manasong, you should be able to pay enough attention to what is going on to see when its needed. If manasong isn't needed and there are mages in the party, then you should use foe's requiem. The only one that is tricky and I don't blame bards for is the TP song in melee heavy parties since you can't see what their TP is at.
As much as you may want to be just a ranger, your are in fact a bard. Your songs are a key part of your job, so please use them! D: