Savage level content has a lot of mechanics which you can skip with high DPS.
Staying in Shield oath the entire time is slowing you down and thus causing your static to deal with more mechanics.
The only time I am in Shield oath is when I do my pull or when we have multiple people down and I need to make the life easier for our healers.
A10S i only go into shield oath right after adds phase for a few seconds as I'm usually out of CD's then. (Hallowed ground middle button mechanic cheesing FTW!)

A WAR OT or NIN will greatly boost your DPS as well as others have said.

Our BLM pulls crazy levels of aggro even with quelling strikes and me in opening in shield oath. He. Must. Get. It. If your BLM is anywhere near that level of damage as ours, I feel for ya.

We use a BRD instead of MCH, both classes have their pros and cons. We have quite a few casters thus Foe's Requiem is a great damage booster for us. Bot are good and acceptable.

I seriously recommend not using FoF with RoH combo.
Especially if your healers are forcing you to stay in Shield Oath, you don't need that extra enmity. What you need is extra DPS.
As others have stated, always make sure you use it before Goring blade. This way you can use it 2x during FoF. Goring blade when it ticks for 75% is our biggest damage skill! Royal Authority might be our direct damage skill, but goring blade deals more damage.

Sword Oath tanking is a lot different than Shield oath tanking in savage, it is key to use cooldowns smartly, properly, plan ahead and mitigate the correct damage types at the right time.
A9S Scrapline? 1x RoH combo when he uses stockpile, Shelltron and a normal guaranteed Cd (Rampart, Foresight, Sentinel depending on damage levels and healers pre-shielding). Sometimes a CD isnt even needed depending on your healers and team. When i get a crit shield from our SCH, the AST uses disable and our SMN virus? CD is not needed as i'll be taking 0 damage anyways, so plan accordingly and keep an eye on the situation.

Also another tip i can give you is to Force proc your shield bash for a DPS increase depending on if you really need Bulwark/Shelltron or not. Start with bullwark, force a proc. Once it ends and shield bash is nearly off CD? Shelltron and force another. Like I said, smart use of CD's is key. You dont want to force a proc with shelltron for example when a physical tankbuster is incoming!

Your first and foremost job is to tank, this means keeping the party safe, you are that first and last line of defense. Once you got that down, maximize damage.