Why buy Seraph's Embrace?

Patch 8.4 tried to create diversity among starting AP items by introducing an early game power spike item (Luden's Echo), a scaling mid-late item (Archangel's/Seraph's), and a catcher/pick item (GLP) to fill the mana/ap/20% CDR first item.

Unfortunately, this backfired, as Archangel's crowded out the other options, even on champions who struggle to stack it quickly. Several nerfs ensued, eventually resulting in Archangel's only converting 1% max mana to AP, and Seraph's giving 3%.

8.9 saw the dubious, ham-fisted decision to cut most mages' mana per level in half indiscriminately. While things have stabilized somewhat, the problem is that a lot of the champions that would WANT to buy Tear in 8.8 lose so much AP because of their halved mana growth.

Specifically, Cassiopeia, Karthus, and Syndra used to have some of the highest mana pools in the game, to reflect that their kits rely on them repeatedly landing low cooldown skillshots or spamming E while kiting poisoned targets. Consequently, their mana/level was in the low 60s. Anivia and Veigar weren't far behind, at 50.

The problem is losing 15-17 AP, or 13 in Anivia and Veigar's cases. Luden's is giving 90 AP right away, but Seraph's gives .9 AP per level at 30 mana per level, down from 1.8. Until then, Archangel's gives a mere .3 AP per level. The numbers go up marginally for Karthus (30.5 per level) and Cassiopeia (31.5 per level), and Anivia and Veigar get .75 AP per level from Seraph's, and .25 from Archangel's.

Considering games infrequently go to level 18 and level 11 is pretty standard for mid game, we should compare a fully stacked Seraph's at 11 to Luden's.

Anivia 114 Cassiopeia 114 Karthus 115 Syndra 115 Veigar 114 All (Luden's) 90

So IF you can stack your Seraph's Embrace completely by level 11, you're looking at an extra 25 AP over Luden's Echo. The problem is, with 1% from Archangel's, if you're at 350/750 bonus stacks, you're at a 25 AP deficit from Luden's.

The worst part is, unless you're buying a catalyst item as well, this is the only use you get from Archangel's/Seraph's passive.

The end result is that in its current state, the risks of a mid game half-stacked Archangel's are just as severe as the benefits of a fully-stacked Seraph's. Buying an 850g tear four minutes in is a high variance move with diminished payoff due to the 8.9 mana nerfs and the Archangel's nerf a few patches before.

So, I have to wonder, who is this item for?

Is it for characters who are looking to delay power? If so, the flat AP ought to be buffed by 10 to reflect 8.9's mana changes.

Is it for characters like the ones I mentioned who can stack it efficiently? If so, it ought to have its % mana scaling homogenized between Archangel's and Seraph's, and to avoid abuse like in 8.4/8.5, maybe increase the scaling to 5% but lower the flat AP to 40.

Is it for all of the above, but everyone has to suffer because a certain single champion will abuse this item if it's worth buying? Make Ryze's passive not stack with Awe It's still 1400 mana, 50 AP, and 20 CDR. Even at 5% instead of 8% he'll survive.