The holiday shop should take into account whether or not you already have a skin for a champion
It's pretty clear that the Holiday Shop (The special personalized group of 5 discounts from Snowdown and Lunar Revel) puts a lot of weight on champions you've played commonly or recently. Which is good, as you're probably interested in getting skins for champions you play a lot. However, it doesn't check to see if you already have a skin for that champion or not. While some enjoy variety, others (like me) are happy with just the one skin to snazz up their champ.
But when I go to see what special discounts I'll be getting this Lunar Revel, I'm faced with 4/5 selections being for champs I already have a skin for. During Snowdown it was 3/5 (the other two being champ-skin packages). As I said, I'm already happy with the skins I already have for those champs, so I'm disappointed that I'm basically only given 1 or 2 actual deals I might use when I expected 5.