The original Tarkir block had a cycle of three-color lands to match the sets five clans, such as Sandsteppe Citadel, Nomad Outpost, and Opulent Palace
This shell is in preparation for BNG, and there are several cards in it, of course, that will be cycled out
Rather than focusing on defense, Quickbeam emphasizes the importance of attacking, granting two creatures +2/+2 and trample each time a Treefolk enters play
Ivy, Gleeful Spellthief allows you to spread your auras out across the board while also stacking all these abilities onto your commander
Izzet (blue/red) decks are not known for the ability to ramp, so you'll be spending the first few turns setting up mana rocks for mana generation, leaving your defenses open
That should be an amazing boost