Poison, redstone, and end problems. Also Ideas for snapshots.

I have noticed that poison on any mobs, apart from that of the player, will not work. I also realised that redstone is extremaly laggy, as i had 250 frames, and then activated a redstone line and ended with 50. I also have had troubles getting to the end. Also i just wanted to say that a wither, blindness, and explosive arrow would be SWEET!