I brought it up in the Eva article thread but I have played a few test matches with a base Bg Eva list with 4 Thorn of Amethyst and while its too early to tell I really like it.

We play
4 Stalker
4 Goyf
4 Specter
3/4 Some dude

That's 15/16 creatures, which is more than most good decks in the format given that we attack their manabase and hand anyway it seems like a strong card. Obviously if you can get it out, all combo decks but Ichorid need to deal with it before going off. It protects you from Daze (which absolutely busts this decks balls) and causes people to have to make decisions in the early game like...do I want to tap out and play something or keep a mana up for a FOW/Daze or whatever. It fundamentally skews a large part of thresh holds plan (ponder for 2? ICK) while giving us a little more time to lay down big dudes.

If we are the tempo deck then let's steal more tempo from the opponent.