Remove Divination CD?

[Lodi]

No. You can completely ignore seals in the opener because statistically you're most likely get the 5%. Even if you get the 4%, it's still worth it over delaying for 6%, because you're stacking and aligning Divination with other raid buffs (and your own cards). Being forced into 4% divination after the opener is extremely unlikely.

By group DPS I'm assuming you're talking about something like 80k. If you're going to call 0.5% "extremely small", then calculate this:

RDPS statistics on Titan: WHM 6.4k, AST 6k
6.4k - 6k = 400. The difference between AST and WHM rdps is extremely small. "Barely 0.5% of the group's dps."

It's easy to downplay the contribution of AST buffs if you compare to the group's dps - a.k.a. comparing to the combined contribution of 8 players.
"Barely 0.5% of the group's dps". Let's just ignore the fact that it translates to 5%+ of the AST's rdps. Let's ignore the fact that it's a loss about the same as (or even bigger than) your DRG using or not using Battle Littany. Or your NIN using or not using Trick Attack. Or your SCH using or not using Chain Stratagem.

Now let's stop comparing it to the combined contribution of 8 players and instead compare it to the AST's dps. The difference between bad Divination/card usage and good Divination/card usage will be over 10% of the AST's contribution.

Divination is the strongest raid-wide buff in the game and can account for over 1% of the group's dps. You're spreading misinformation.

And you didn't read what I wrote. Try doing that before calling me a liar.

I said that optimizing Divination barely makes a difference. By spamming cards and using Div whenever available, you're already getting to 2/3 of the optimal buff numbers; aligning seals and using the right cards barely adds to the pile.
Oh, and make sure not to clip any of your redraws, because you'll waste a Malefic and it would kinda ruin the point of aligning seals.

Most classes get awful numbers if they don't use their kit correctly, but AST still gets most of its buffs by just puttings cards on the best DPS and using Divination whenever. It's ridiculous.

Besides, if you really, really want to squeeze a bit more damage, then play WHM or SCH. They're still far ahead. Hell, even Chain Stratagem sometimes gets better results in one single button press.
There's no real point in theorycrafting AST right now, because the result will pretty much be "more work for less results than the others". Even in top tier teams.