A bigger Violet Teacher, and perhaps better in the right deck.
PROS:
- 4 more power for just two more mana
- Makes 2/1s instead of 1/1s
- Triggers off of any card, not just spells
CONS:
- Still has only 5 health; dies to Lava Burst/Fireball
- 7 power makes it vulnerable to Big Game Hunter
- Can only use 1 in a deck
Of course, you could always use two Violet Teachers and one Illidan. That's what I do!
6
Paying 3 overload for gaining 4 mediocre cards with a high chance of synergy in between them at the later stages of the game; sounds like a good deal to me :)