You can't really compare Dota Itemization to LoL itemization, as they're built in two completely different ways. There is no "AD" or anything comparable. Instead, there's Strength, Agility, and Intellegence (Wisdom? whatever this one was). And Heroes are predefined with which stat increases their basic attack damage. If you're on an Agility hero, and you build strength, you get HP, HP regen, and something else I think, but you do not get any buffs to your AA.
As a result of these differences, Dota 2 itemization is hugely complex (and imo overly so for no good reason, just like the rest of the game, but that's just me), and you can't say "AD Dota Heroes can use their new spell vamp item" because there is no such thing as an AD hero. Thus, your thread is inherently flawed in its logic, and your criticism is a failure.