I would like to point out some of the things that may be missing or may be impossible to create using CEs:
Speed of the chain-explosion
As you may or may not know, there is an element that has that special feature, the Black Orb Bomb. I don't there there is a feature that has to do with changing the chain-explosion speed.

Dragon... properties?
The dragon's main feature is that it breathes fire, yes, that. But what I want to know is how can this be recreated? It's more like this: flame 1, flame 2, and flame 3 instantly from the mouth of the dragon. But trying to use CEs with the dragon and three flames, it's flame 1, per frame, flame 2, per frame and so on. Another problem, if the player gets in the way of the flame, does it kill the player because of the CE properties trying to recreate the flame in a harsh way, or simply blocks it unlike the normal properties (as in flame 1, player, flame 3; regardless of the player blocking the flame)? I think this one may not be recreated at all...
Gravity trigger
If you guess what it is, it's the gravity ports that trigger the player to either fall onto the ground, or stay afloating as if your standing on the “floor” (the empty space). There should be an trigger effect for this, in the action box in the change section.
Maybe I am being too harsh on the elements... mostly because of how the objects are distinctive from ever being created. Especially the dragon, ;o Sure, the RnD elements may be stuck in the game editor forever and ever; but the CEs I had to admit are exceptionally flexible. You can transfer your own creative elements into another levelset and place it there like it's for the stuffing. You can add content and stuff. Somehow, I think this topic is suddenly turning to some CE ideas page, or maybe an ideas revival page that some people may have missed. So... I have no idea where to put this topic... General Discussion, or New Ideas. Your call...