I would change Simulacrum to "When an attack would kill you the damage is transferred to your summoned creature"
That way you couldn't just make a melee combat character and summon something far away from the battle for an easy god mode.
Hmm.
In the OP, I changed the core mechanic behind Simulacrum (but not its intent) and renamed it Soul Harvest. The new version strongly encourages you to keep your summon (or a charmed enemy, I guess) nearby.
Also added Savour the Moment.
edit: Added "within Sight" to Soul Harvest, to prevent weird cases involving party splits. This also means Blind turns it off.