There is no good reason for it to be a gamble on the one that you want. It's pretty obvious that players don't like it, which is why a lot of people won't buy them. Some will, but your revenue would be a lot higher if you just let us buy the ones we want.
Riot I promise you, unless these new little legends have a guaranteed drop rate, they won't be that popular.
For those of you who aren't quite convinced, I did the math on the odds of getting the little one you wanted:
Assuming we buy just a single egg, we are already given a 5.5% chance of getting the Little Legend that we want. (In my case, it's the Winter Cherry)
If we buy the 10+1 pack, that chance is boosted to a 60.5% chance of getting the Little Legend that I want. So right away, we have to spend $35 to have a chance to get the Little Legend that we want. That's pretty scummy.
But what if we want to level it?
Well, assuming we have slightly bad luck, and get 1 for every $70 spent; that would mean we would have to spend $210 to get the Little Legend we want to level 3, and again, this isn't guaranteed. You still only have a 5.5% chance of getting the Legend you want from each egg, and I'm not even sure if they disqualify duplicates. (Meaning if you already have 3, will you get another?)