Phantom Dancer I feel should give you lots of bonus movement speed when strafing a target, rather than damage reduction. If the idea is to "dance" around your target, then gaining bonus movement speed when moving around them, and not necessarily moving towards or away from them, would allow the wielder to dodge incoming projectiles better, instead of making them better at facetanking them, as is currently the case. Making the bonus movespeed exclusive to strafing could allow for mobility that isn't directly linked to closing or widening the gap between the wielder and their target.
DD I think is pretty much designed to be healthy when used by melee champions: when you're melee and just survived a burst of damage that would've killed you thanks to DD, it's a race against time to find a target to heal off of before you die, and so the effect has both interesting gameplay and counterplay (you can kite the melee DD wielder at a crucial time so that they bleed out). On a ranged champion, however, it simply becomes a question of hitting whichever target is in range, so the bleed gets countered without too much trouble, and the item ends up basically providing 30% damage reduction. Because of this, I think the damage conversion effect needs to be either made melee-exclusive, or should be different depending on the target's range, e.g. 30% on melee champions and 15% on ranged champions.
The fundamental issue with life steal, imo, is that it's a stat whose sole purpose is to allow drain tanking, but which scales off of damage. It's currently excessive right now, but even as a baseline it gives durability to classes whose weakness should be a distinct lack of durability. The only class who I think would be justified in picking it would be fighters, but otherwise marksmen should not have access to this stat, at least not in an environment where damage is reasonable enough to not completely cream them the moment they get exposed (which happens especially when they get focused by the entire enemy team).