So when does this Smart Loot start to kick in? .
There's no such thing. Literally the only part of the game with actual "smart loot" is ships and shaders from faction rewards packages. Crota's End had "less dumb loot" and VoG had "repeatedly dropped on its head as a baby loot." KF loot tables don't care what item you got last week or last encounter this week, and they sure as hell don't care what Light level it was.
From 3 raids today I made exactly 0 Light level progression across all my characters. After 14 full raids I've received 0 helmets and exactly one drop at 310 Light: the garbage fusion rifle. Feels bad.
The system in Crota's End was very reasonable and about as good as we could hope to expect. The weapon distribution was bad which lead to some unlucky #ForeverNoHammer members, plus it forced you to run NM Scrota before HM each week. But the armor was great since they divided it up well between the encounters, i.e. you wouldn't go very long without gauntlets since they were the only Abyss armor drop.
KF threw that out the window and crammed most of the armor drops into the Golgi encounter. Technically the class items are armor and they drop from Daughters. Oryx supposedly gives helmets but the drop rate is so low even Luke told us not to hold our breath. The "20 mouldering shard drop" is so diluted with every raid weapon and armor plus all the exotic weapons and armor that odds are razor thin you'll get the one piece you're missing. Then you'll need to hit the jackpot again with a high Light level when most drops skew 300-305.
Basically it's a mess. The saving grace is that the new Light system is much more forgiving of under-leveling than Year 1 Destiny. The catch is we still don't know anything about Hard mode, fingers crossed that being 308 to 310 Light will be about the same.