Are you somehow "handicapped"? The Healers were in DL/AK as well(to get their Relics) and Garuda/Titan Weaps...
There is nothing on Titan that can one/twoshot you...NOTHING. Mountain Buster are the only "dangerous" moments, but people know when they are coming, so I get Stoneskin and Adloquouium before it hits and I barely get below 50% HP...Virus, Eye for an Eye, Rain of Death...all ways to lower the dmg as well...

You must be in a FC with some really bad players...according to your description a WAR would never be able to tank Twintanie on Death Sentence ever...which has been done several times (with said Stoneskin/Adloquouium) tactics...if you can't rely on your group to do whatever they can to help mitigate damage, don't bother trying Twintania...you will never succeed.
You win, me and my FC are just idiots and obviously the WAR tank was just fine as it is and the changes aren't needed and we are now going to be OP as it allows us idiots to complete content we shouldn't.

Re-rolling PLD..........