I am thinking about adding the escalation die to my 4e game. Maybe I will try it next session.
One interesting effect is that it reverses 4E habits. Many 4E combats start with the big powers being fired off at the start of a combat, and the combat tailing off with a whimper as the PCs whittle down the monster by plib-plibbing with the at-wills which are all they have left.
The escalation dice encourages folks to save their big guns until later rather than blow them early. The result is that a combat builds towards a spectacular climax rather than dissipates into a lengthy attrition. It's really rather clever.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.