There are plenty of creatures above 4 HP.
In fact the bump from 3 HP to 4 is probably the most important one in the game!
Pretty right, but not exactly. If you take the flying weapon into account, and count upgraded version as differents mobs, here are the number of creature for each HP:
0 HP 2 creatures
1 HP 25 creatures
2 HP 24 creatures
3 HP 21 creatures
4 HP 14 creatures
5 HP 17 creatures
6 HP 13 creatures
7 HP 10 creatures
8 HP 5 creatures
9 HP 4 creatures
10 HP 1 creatures
11 HP 1 creatures
12 HP 4 creatures
25 HP 1 creatures
30 HP 2 creatures
70 HP 2 creatures
So right 50% of all creature are under 3 HP. But above it is a pretty consistant 10% for 4Hp, 5HP, 6 Hp, and above 6HP.
Anyway the more I play the game, the more I feel that "Rain of Fire" is the ONLY way to mass creature control. And compares to that we have "Boneyard" wich can spam creature pretty easely.
So basically this "Mass holy light" should be an counter to boneyard deck. Unfortunatly the way the system actualy work (killing creature in order, and generating them right after with boneyard) turn a "mass holy light" in something that miss its purpose, in term of Roleplay (still skeletons walking after the Mighty Holy Ligh), and in term of gameplay (decreasing usefulness against death element).
And having the card destroying the Boneyard in the process to ensure no regeneration of skeletons, would be far too much.