Long, loooong-standing debate, especially over at
Vanguard Crafters. What usually gets mentioned sooner or later, as I'm about to do, is that Mr McQuaid absolutely DOES NOT like item decay. Which means we're very, very unlikely ever to see it in Vanguard.
My opinion is that it would solve an absolute host of problems, and that you can *so* easily work around the negative scenarios Brad quotes. You can flag certain items so they don't decay (bound or not). You can flag *soulbound* items so they don't decay. You can... and so on.
But I'm not holding my breath. This is an item-centric game (read : loot uber alles) and one without meaningful decay (read : welcome to the glut) and since both these principles are dear to the heart of the prime instigator, they're not going to change anytime soon.