They are already thinking in this direction... making elements of the game "common" "uncommon" and "rare". Common elements being those that are basic to the game, uncommon elements are ones that are popular, but can easily removed from the game, and rare elements are those weird/interesting things that have a small fan-base, but isn't really popular.
Examples: Fight (common), Barbarian (uncommon), Psychic Warrior (rare).
Alternatively: Elf (common), Drow (uncommon), Winged Elf (rare).
YES!!! I had forgotten about that. So common = tier 1, tier 2 = uncommon, tier 3 = rare, and tier 4 = theme. I may have to go back and edit my original post...