Your deck needs to be laser-focused on creatures to keep drawing cards, which makes this deck abysmal at responding to changing board conditions
Its a powerful trade-off, but not the easiest one to use (particularly since it only taps for colorless mana otherwise)
If you can find them at MSRP, snap them up, but you should be prepared to pay a fair amount for each
If you have some other crazy idea up your sleeve, you can use a card like Baral, Chief of Compliance, which works as a creature and helps lower the mana cost of Time Stretch
What makes her stand out is her Ready ability, allowing you to Ready her whenever you heal one of your Characters
A bunch of other cards are affected by this