None of us have ever run it legit. Ever. Every single one of us have never done anything other than push templar off so we have zero idea of the strategy that works
I really hope there's no way to cheese sections of the new raid. A group I ran with took an hour or so to beat Templar last night because no one but two if us had ever tried to fight him on hard.
Relying on cheese makes for bad habits.
It's not a difficult encounter. No single element is particularly tricky to manage.
Harpies do little damage by themselves, you just need to make sure they don't overwhelm you. Relic holder can smash them for super regen. Use class abilities that generate orbs.
Kill oracles. If you miss one wait to cleanse before dropping shields. Send two out to kill any Oracle you can't get line of sight on. One to kill the Oracle and one to cover.
When shooting the Templar spread out a little so his barrage isn't hurled at everyone at once. If it's coming your way then be cautious.
If you see the red circle when he's about to teleport as you damage him and you're a Titan with your super ready them jump on the circle and throw up your ward. You'll keep the Templar exposed for much longer as he won't be able to teleport and recharge shields for an extended time.
Stick together so you can cover each other but don't stay too bunched. A good position is the back right cave platform then alternating by moving down in front of the door at the back in the middle if the Templar moves too close.
Main tips:
Kill oracles.
Manage harpies.
Stick together.
If using rockets set positions when firing to avoid misadventure.
Play defensively but make the most of Templar shield downtime - IWoL helps a lot. Use it!
Don't panic: nothing can one shot you here unless you die by misadventure.
Modify the above to suit.