I don't like Amalgams, since they only enter EOT. On the other hand, the deck is fast enough as is, so I might give them another run.
Honestly I loved them, no one is ready for an Ichorid that sticks around. I am playing for the grind tho, so in a speedier build I think your evaluation that they're too slow to be effective is correct.
Next time I might drop blue and play Leyline of the Void, Unmask and Street Wraith/Gitaxian Probe for speed. The first is better with Ichorid and Unmask, the latter with Cabal Therapy.
I tried this! Wish I had seen this thread for the validation haha, but check out my report here for Unmask thoughts. Tl;dr it was gr8. http://www.themanadrain.com/topic/768/november-vintage-in-berkley-ca-dredgedredgedredge