Currently upgrading the manabase, because I want to be able to run Counterspell rather than Mana Leak.
I was thinking the same thing. Another thing I'm considering is axeing Feeling of Dread, Gideon, and Sunblast Angel entirely, and adding in things like Sun Titan. That said, running Reveillark and Sun Titan, I need to make sure as many creatures as possible are able to be pulled out of my graveyard, and while Restoration Angel doesn't fit those bills, she's great for getting a blink effect and another ETB trigger.
Here's a version 2.0 that I put together. I think it's a bit of a stronger build.http://tappedout.net/mtg-decks/uw-venser-control-copy-07-11-13-1/