From the oficial forums:
http://us.battle.net/wow/en/forum/topic/3595575395

Hello! I just read a bluepost about the new talent trees and Bashiok said they needed feedback on the (pre-alpha) talent trees, so here's my concern I really hope a blue reads it, an in any case please discuss:

I had leveled a warlock in another account in wotlk and it was time consuming, mainly because our self heals were pretty bad as anything but affli.

I leveled this toon during cata and it was awesome, never needed water/food i could just lifetap to full mana and soul harvest to full health (between pulls). I also feel like i'm less of a burden to the healer between pulls in end game content (good healers know i can use my lifetap/soul harvest combo to full, so no need to spend mana on me)

I love the soul shard change coming our way in MoP, however, I really feel we need something to compensate for the loss of soul harvest. It was a great change and an awesome spell which really felt warlock-y. If more people tried it, maybe warlocks would stop being the least represented class in the game.

Please, reconsider this change, add back soul harvest or add a (default, non talent) similar spell.

This is just a quality of life issue, i'm sure our dps will still be awesome, but for me it's all about questing/playing without having to sit down for 30 secs every other pull.

Thank you and /discuss

TL;DR:
Harvest life is great, please let us keep it in MoP