Did the camp mechanics change?

When I started jungling, it was common, while stealing a camp, to leave one small creep in the camp, because the camp timer doesn't start until that last creep is cleared.

I just realised, watching worlds, that nobody does that anymore. When stealing a camp, they always full clear it anyway.

Did the mechanics change since Season 3-4, or is it just now more advantageous to full clear the camp over leaving one creep?

The old camps, like wraiths etc... it was common to leave one small creep at the opponent's camp because it hurts the enemy jungler more. But now since the EXP is shared across all the creeps upon clearing the camp instead of just the big one, it actually hurts you more than the enemy jungler.