Some of the seasonal stuff delivers %-based health. There's also something from a treasure in Draenor that heals 60% health/mana over 30 seconds. But yeah, Draenor food has very poor healing values. Doesn't take much gear to get 340k health. If you're outdoors you can build a gladiator sanctum. One of it's levels gives you faster health regen while outside in Draenor. On my Warlock it's almost enough to negate the Burning Rush talent.
Graccu's Mince Meat Fruitcake was buffed this last Winter's Veil to 20% hp/mana per sec, with a duration of 10 sec. Full hp/mana in 5 sec from 0, if you prefer. Availability only on Winter's Veil.