I like the combo and I see what you are trying to do with it. I just think it's a bit slow.
You only use Green for
Gift of Paradise and it's nice for the life gain and color fixing, but I can't see any other green cards.
Maybe replace those and include 3-4
Chromatic Lantern's for speed up and color fixing. Alternatively Powerstone Chards, but then you'll need your white and red colors from elsewhere. You are not going to cast your
Chance for Glory before turn 6-7 anyway, so by that time you should have your mana fixing in place.
You could then do a
pure Dimir variant using slightly clunkier black board wipes. You could use
Phyrexian Scriptures or
Ritual of Soot instead of the white ones. The deck does not have any creatures, which is fine, and results in a lot of useless cards for the opponent at least in the first game. To get most advantage of
Phyrexian Scriptures, it might be good to include some hexproof or indestructable creatures.
Nightveil Predator or
Slippery Scoundrel could work. The first one can block Ghalta once and the second can sacrifice itself blocking a
Steel Leaf Champion. These creatures are not perfect, but could
serve as an alternative wincon later due to their evasiveness when you take all those additional turns.
Nightveil Predator obviously the better one as it combos with both board wipes.
Being more in blue would enable counterspells. You could have a couple of Devious Cover-Ups to return some of the combo pieces back to the deck and have Unexplained Disappearances and Sinister Sabotages for some surveilling. If you go the surveil route.
Thoughtbound Phantasm would not be a bad creature to include despite not having indestructable or hexproof.