As for why it was changed from the alpha - when it was so good it made other good things look bad, especially in conjunction with the Rogue. This wasn't so much of a problem in and off itself, but it was affecting the way testers look at thing, and the game was rather too hard / all over the place because people were content that, say, vicious dungeons were beatable with a cydstep rogue. Shelfing the idea for a while led to a lot of adjustments that brought some classes up, some classes down, and made most of the dungeons much more approachable.
The strenght of the cydstep rogue strat also helped develop a "scumming is legit" mentality. So not only did you have a really strong strat that can be suggested to people struggling with a dungeon, it was also one where you had to repeatedly restart looking for the glyph.
It wasn't the only thing that got shelved this way, stacking bonus damage on orc conversions was also cropping up everywhere so the devs even said "we're removing it so we get dungeons beaten by something else for a change" or something to that effect ("Test other stuff guys!").
As I've said - now that it has you looking at both your health and mana, as long as you're not a warlord, it's probably not going to be as disruptive - and we tested so much other stuff too