The deck seems very slow and it will have problems vs aggro and burn --> I would remove the slowest cards which dont do muvh on their own:
Herald of Secret Streams,
Murkfiend Liege (he is good, but on his own he is a 5 mana 4/4),
Mitotic Slime (reduce to 2, on his own he does not do much, again a 5 mana 4/4, yes he is good if the opponent plays black and only destroy not exil), also
Zameck Guildmage, he seems not so slow but what is he in this deck... you play him turn 2 and then... you need 2 mana to activate any of his abilities and they than you still need to play a craeture which costs ~3 mana = 5mana very slow
maybe add a manadork (1mana elf)
vs tokens you can play
rancor (instead of unblockable)
also is there a reason why you dont play
Experiment One and
Scavenging Oozei hope that helps a bit, and have fun building