Basic Math - The Failure of Diablo Melee

[Elric of Grans]

One of the biggest and most frustrating problems I run into in Inferno (act I) is not so much the boss abilities as it is when particular monsters are promoted to boss/champion

That is exactly what I have been saying to people. I have faces packs that had the same combination of abilities, but were different base-type creatures. In one case it was a piece of cake; in another, it was a nightmare. Certain abilities are stupidly powerful on certain creatures (especially anything that already teleports, or has some kind of a special, telegraphed attack).

Inversely, certain abilities make certain enemies a lot easier. Ranged enemies with Waller? They block their own attacks while you just use attacks that hit around them I love it when casters that normally run-away from you have Vortex!

In my experience, I have never once faced a Unique enemy that was felt over/under-powered. Because their abilities are predefined, they are always perfectly balanced. The randomness of Champions/Rares makes them considerably less balanced, in both directions.