Shinryu wasnt "EX" levels of difficulty.
Shinryu had insta kills, but with no DPS check, you can just infinitely keep rezzing through it. (Which my groups loved doing.)
Not exactly how EXs work.
By this logic, Titan normal (not hard) is far harder than shinryu. Not only does he have insta kills, you're not even allowed back on the field.
So many people complained about titan normal back in the day, and he was also required for story. And you didnt have the ability to out gear him to the degree you can with shinryu.

Shinryus REAL challenge, and REAL problem, is that it has 3 attacks with little, to no conveyance.
Tidal wave.
Do you get near it? do you avoid it?
BOOM DEAD.
This one is only ok, because its RIGHT at the very start.
You learn right away,a nd at least how to handle it is conveyed instantly after u die to it.
So its ok.
DPS gets targeted with a lingering attack on the ground.
There's nothing to tell the DPS they can move out of the attack, other than, literally moving out of the attack, and finding out.
Also, not so bad, so it can technically pass as acceptable.
Tanks share an attack
This is the one where theres no visual indicator they need to share dmg, AND theres no indicator that easily tells you if you're doing it right.
Even if a tank runs by, and hits one of the attacks, you dont go, "oh, I took a tiny bit less dmg on one of the ticks there!"
Its much harder to figure out. And has been reserved for EX content prior. We only knew about it, because its happened in those EX/savage fights, and heard about it.
This is the one that needs to be conveyed better.

Back on topic, Hades is super easy, and needs more focus on insta kills. (And of course no real DPS check, so you can just keep reviving people up) but I assume the reason they didnt do this, is because its much harder to do now, with less means to maintain MP. So they probably decided to go with a more classic design. (They should still go back and up Thoradans difficulty a tad, not like it would be hard even with more dmg dealt. Plus Ultima should have been a separate fight, so it can also be upped a tiny bit, closer to what Hades is now)