It seems to me that the way the gold value of each statistic is calculated is very arbitrary and that slightly changing the definition completely changes the value of certain statistics.
To illustrate my point, here's the current gold value of each stat when you use the most expensive item that has only one stat, instead of the cheapest.
Champion Statistic | Base Item | Item Cost | Stat Raised | Gold / Stat Bonus | Difference with Current Model |
---|---|---|---|---|---|
Attack damage | 1300 | 40 AD | 32.5 | -7,14 % | |
Ability power | 1250 | 60 AP | 20.833∞ | -4,21 % | |
Armor | 800 | 40 Armor | 20 | 0 % | |
Magic resistance | 720 | 40 MR | 18 | 0 % | |
Health | 1000 | 380 HP | 0 2.63 | -1,38 % | |
Mana | 350 | 250 MP | 0 1.4 | 0 % | |
Health regeneration | 150 | 50% HP5 | 0 3 | 0 % | |
Mana regeneration | 125 | 25% MP5 | 0 5 | 0 % | |
Critical strike chance | 800 | 20% Crit | 40 | 0 % | |
Attack speed | 300 | 12% AS | 25 | 0 % | |
Flat movement speed | 300 | 25 MS | 12 | 0 % | |
Life steal | 900 | 10% LS 15 AD | 41.25 32.5 | +10,00 % | |
Lethality | 1100 | 10 Lethal 25 AD | 28.75 32.5 | +27,78 % | |
Magic penetration | 1100 | 15 MC Pen 45 MS | 37.333∞ 12 | 0 % | |
On-hit damage | 1000 | 15 OH Dmg 25% AS | 25 25 | 0 % | |
Cooldown reduction | 800 | 10% CDR 200 health | 27.4 2.63 | +2.75 % | |
Percent movement speed | 850 | 5% MS 30 AP | 45 20.833∞ | +13,92 % | |
Critical strike damage | 3600 | 50 Crit 70 AD 20 Crit | 26.25 32.5 40 | +50.00 % |
As anyone can see, although only a few basic stats are modified (AD, AP, HP), and the variations are relatively modest (less than 8%), the derived gold values for some stats see massive changes. For instance Lethality gains over 27% in value, while Critical strike damage gain 50%.
Can anyone justify why picking the small items is better than picking the larger items ? Both seems as arbitrary to me.
I would also point out that a small modification to the objects that are used as defining objects, like the Long Sword will modify the gold value of dozens of items, whereas any changes to these dozens of items will not modify the gold value of the Long Sword. This asymmetry should not exist in a good model, where if an object can modify the gold value of a stat, then every single item should be able to influence the gold value of the stat (the influence can be zero, but it should change depending on the stats of the item, not because we decided so).
EDIT: The only thing I want is a disclaimer that states that the method used to calculate gold value is arbitrary and should therefore not be taken as an absolute truth, but more as an estimate as to what each stat can be worth (as we've seen that there can be over 20% variations on some stats, just by changing one word in the method).