I was looking around and found some neat cards that would fit really nice into the deck:
Mwonvuli Beast Tracker: Lets us tutor any creature in our deck and combos well with Descendants' Path. Also gets Acidic Slime to remove threats instead of Relic Crush, it's deathtouch is useful for Prey Upon.
Assault Formation: Permanent boost to our thoughness-heavy guys with a additional ability to firebreath, untapping enchanted lands with garruk can make this devastating.
To get these cards into play some need to leave the deck, 3 Arachnus Spinner should be enough since it has high cost and can be tutored. through this combo chain you can also tutor Arachnus Web, so one could be removed to make some room.
Overrun can hit hard, but I'd rather have a permanent boost through Assault Formation than one single chance, the trample can be compensted by the webs and by pumping up unblocked creatures (and Garruk can also give trample).
Since I still would need some space I'd have to remove a creature or two, not sure which one I should pick, either Juvenile Gloomwidow or Kessig Recluse. For now I'll go with -2 Juvenile Gloomidow, deathtouch is better than wither (but it also costs less...hmm...).
So for now we got:
-1 Arachnus Spinner
-1 Arachnus Web
-2 Relic Crush
-1 Overrun
-2 Juvenile Gloomwidow
= -7
+3 Mwonvuli Beast Tracker
+2 Assault Formation
+2 Acidic Slime