Sunfire Cape is not a fair first item for top lane tanks: a cost and usage analysis

What I mean is, it isn't fair that it's the only real first item option for top lane tanks despite the myriad of problems it has when compared to the options for every other class:

1. It is by far the least gold efficient first-buy option of any class, at only 85%. Not even including their passives, all of which are better for their classes: 100% 97% 111% Reaches 100% at 328 mana. 104% 112% 92% 108% 95% 93% 121% And bear in mind, this is even AFTER a price reduction.
2. That first problem exists despite the fact that top lane tanks are the champions least able to farm, since they can't reliable win trades or duels against a Fighter-class opponent of equal skill.
3. Despite these champions being at that disadvantage when it comes to farm, Sunfire Cape has a passive that directly hinders your ability to control a wave or farm under tower.
4. Despite the kits of any champion who does build black cleaver first already being counters to tanks, its passive widens the gap between it and Sunfire to comical levels. (my full analysis of that is available here, though sunfire did recently get a 150g reduction, so take that into account https://boards.na.leagueoflegends.com/en/c/gameplay-balance/5FsJfYi6-sunfire-cape-costs-more-than-black-cleaver )
5. Even though top lane tanks have some of the highest mana costs and cooldowns of any champions, their best (but still bad) option to buy first doesn't provide any mana or CDR. And if they do choose to buy mana/cdr with Gauntlet/Heart, then they won't have enough defense since they won't have health.

Now, I'm not saying that Sunfire should be changed. Personally I think it has no place in the game since its waveclear is only really good for splitpushing, but tanks need to be with the team to engage/counterengage by the time splitting becomes viable.

I think a new item should be introduced to actually give tanks stats they need, like a first item should.

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With that in mind, I want to discuss why Sunfire is in such a terrible spot and what a replacement could look like. The main culprit is the Tank "Update" of 7.9, which saw the reduction of total effective health across the board for all tank items with health. What that means, and which was actually their stated intention, is that you get less defense against magic when you buy Sunfire and less defense against physical damage when you buy Visage.

But I do not think that that should be the case for a starting item. There should be a single tank item which is an exception to that rule, granting just enough flat HP and the CDR/mana a tank needs to deal with their high costs and cooldowns, without any offensive stats for fighters to abuse. My suggestion is:

Breastplate of Valoran: Cost- 2900g Components: (800g) (1100g) (400g) Combine Cost: 600

500 HP (600 with the passive) 350 Mana 10% CDR (20% including Haste) Unique Passive: +100 HP (since those items would add up to 575, but I don't want people to just stack a bunch of this) Unique Passive: HASTE: 10% CDR Unique passive: Self shields (only shields) are 10% stronger

600 HP, 350 mana, and 20% CDR would total 2626g in stats, making the item 91% gold efficient not including the shield passive.

(for comparison, Sunfire has 680 effective health against physical damage. Just so you don't look at 600 and think it's too much without realizing I'm suggesting an item with neither armor nor MR)