Are your healers well geared? Is one solo healing the fights? Which jobs are your healers? Since it could be that your healers are not performing optimally. If they require you to be 100% in tankstance because they complaining about the damage you taking then you need to manage your CD's properly or they need to know how to precast their heals properly.
Having no NIN is not the end of the world, just you holding yourself and the DRK back in DPS.
The BLM I would actually highly suggest that they get Quelling Strikes since not having it in a raid environment is just bad on their side since it require you to use more of your aggro combo rather than your Royal Authority combo... and if they not having aggro issues without Quelling then they are doing something wrong on BLM.