Never saw a density control. There was a gravity control for Controllers and Dominators that had some phasing powers that used to make me think of The Vision - only that was more about 'caging' a foe. Then there was the Phase Shift at the top end of the Concealment pool, which had such a long recycle time you couldn't do much but escape a wipe (why can't I walk through these walls again?). A defensive power set built on this premise - lots of defense mixed with a couple phase outs - would have been awesome. I could see tankers working phase shift with taunt as easily as stalkers working it with placate. Maybe not much on the regen angle, but still nice. Those intangibility enhancements always seemed so lonely. Such a small segment of the player base messing with that kind of thing. Sandman, ghostly fadeouts; all sorts of great themes could have been worked into this. Sigh.