I have been poring over the xml as I make my new items and abilities. I thought I'd share what I've found regarding the rarity values, in case it would help anyone.
(FOR ITEMS) It seems like the rarity is controlled by these two variables:
<Liklihood>200</Liklihood>
<RarityDisplay>Rare</RarityDisplay>
Now, I've seen various "Liklihood" numbers for different "RarityDisplays," such as
250+ - 400 Common (gray)
200 - 250 Uncommon (yellow/gold)
150+ - 200 Rare (orange/red)
100+ - 150 UltraRare (dark red)
0 Unique (purple)
This said, there are instances where there are UltraRares at 250 and Rares at 200+
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As for abilities, for some reason, the xml is slightly different:
<Likelihood>200</Likelihood>
<RarityDisplay>Uncommon</RarityDisplay>
*notice the "e" in Likelihood, why? (this is the correct spelling)
Does this mean that in one set they may work and the other they don't? Two separate variables for the same objective?
"Likelihood" ratios for abilities seem to be as follows:
400 - 600 Common
200 Uncommon
100 Rare
5 Rare (Path of the .... abilities)
Notice there are no UltraRares nor Uniques.
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I have noticed that the abilities I created, although working as intended, when a sov or champ hits the level prereq:
<Prereq>
<Type>UnitStat</Type>
<Attribute>UnitStat_Level</Attribute>
<Value>9</Value>
</Prereq>
The ability, without fail, becomes a choice, though I have set all my new abilities to 50 or 100.