Lifesteal should go the way of spellvamp

Lifesteal is spellvamps cheaper and more reliable cousin so why is it that riot saw fit to utterly delete spell vamp from the game and lump it clumsily into ONE item (that also happens to double as lifesteal) but they have left lifesteal alone. Lifesteal is way more consistent as auto attacks have no cooldown and can hit as hard or harder than spells at this point in time. Im looking at you 1200 dmg crits.... What I am proposing is they do the same thing to lifesteal as they did to spellvamp, i.e confine it to specific items and remove it from low tier items. There is no feasible reason why an adc with just a dorans blade should be able to heal 200 dmg in an instant when they get their infinity edge and land a single crit. Or an assassin like kha should be able to sustain himself that easily. Its been egregious for a while but I sincerely thought riot would handle it.