About the manabase, I personally wouldn't run the bad fetches (e.g.
Mountain Valley) and
Temple of the False God. For the fetches, they tend to slow you down, while you usually want to be fast in order to build up your prison. The temple, well, he's fine in decks that have a good land ramp, but otherwise, he can really hurt you if it shows up early on.
A little more basics would be nice, since cards like
Back to Basics or
Blood Moon would break your neck at the current state.
Kormus Bell is a meta call right?
What maybe would also fit into the deck is
Spirit en-Dal,
Soltari Champion and
Soltari Visionary. the first one makes one of your creatures basicly unblockable, the other two are somewhat expensive with cmc3 but are unblockable and offer some utility on top.
For card draw,
Rogue's Gloves might be an option, since you'll try to be evasive.
Unless you have it already, you could replace
Concordant Crossroads with
Mass Hysteria. But this is mostly a budget decision.