K00lDudE1,

First of all, thank you! I appreciate that you've come to like my deck! To answer your questions though, I choose not to rune BSZ (Blue Sun's) because it usually ends up being a win-more card. On most turns, I'm busy using up all of the mana available to me, casting creatures and other cards that help me win faster (such as Earthcraft, Birthing Pod, etc). This makes it impossible for me to hold up UUUX to draw cards in hopes of being able to do something else at a later turn. The only situation I would find BSZ useful is if I have a Seedborn Muse out with no Teferi or lands that help me cast creatures at instant speed. Even then, I would usually only be able to cast it for X=2-4, not drawing me nearly enough cards to command a supreme card advantage over others. In short, the card either doesn't do enough, or does too much (win-more).

As for GSZ (Green Sun's) I keep a spare copy because I realize that it's a very good card. My issue, and why I took it out in favor of Chord of Calling, is threefold:

1. The card cannot tutor at instant speed.

2. The card cannot use creatures to help pay for the cost (Convoke is great).

3. The card can only search for green creatures, and my win-con is exclusively mono-U.

So while it's a good card, I don't find it quite good enough for the deck as it stands. Though it may come back into the deck at some point later on.

Thanks again, and let me know if you have any other questions!