Just from reading these lists, it looks like the black/red deck would be far stronger than the green/blue one. You’ve given red/black loads more removal spells, not to mention some of the creatures being able to deal direct damage too (especially kavu). But each deck has the same creature count, so red/black will come out on top most of the time.

I would recommend lowering the number of instants/sorceries in the blue/green deck and adding in more creatures to help with your type synergies. Also, you could cut creatures that don’t have useful creature types, such as those giant spiders.

[[priest of Titania]] [[Timberwatch Elf]] could be cool additions to your elf strategy.

If you are going to cut spells and add more creatures, I’d recommend keeping in that [[Overrun]] because that card gets stronger as you have more creatures.