You have some good cards, but a lot of them don't go together. It's like looking at a bunch of cool cars and trucks you see in your neighborhood and deciding you want a sports minivan with a flatbed in the back. All of those things together just make it a worse version of each of those.
It's better to focus on one strategy and run cards that are good for that. Priest is usually best using a control strategy, while Leper Gnome only goes in super aggressive decks. Lightwell isn't that great right now and you can do better than Temple Enforcer and Questing Adventurer.
You definitely want a second Cabal Shadow Priest (running two copies of that plus two copies of Shrinkmeister ensures you have a greater chance of getting both when you need it) when you can and instead of Shade of Naxxramas, Sludge Belcher would be a better inclusion.
Minions are way better than Mind Blast for dealing damage.
Light of the Naaru is a really good card you should consider running. Wild Pyromancer helps you against really aggressive decks. Auchenai Soulpriest combos very well with Circle of Healing (but I wouldn't run the Circle until you have both Auchenais).
If your collection is still growing, you may find that Sen'jin Shieldmasta is another good defensive minion.
Also, don't play with Divine Spirit. There are too many silences, bounce effects like Sap, and straight up creature removal to make "building" a minion with multiple cards a good choice. Power Word: Shield draws you a card, so it's essentially free. Velen's Chosen and Divine Spirit are not.
I'm really liking Lightbomb as a super removal for Priest and you should try to get some when you can, too.
You can probably change your deck around to something like this right now:
2 Holy Smite
2 Power Word: Shield
2 Northshire Cleric
2 Shadow Word: Pain
2 Dark Cultist
2 Ironfur Grizzly
2 Shadow Word: Death
2 Sen'jin Shieldmasta
2 Gnomish Inventor
2 Sludge Belcher
2 Holy Nova
1 Cabal Shadow Priest
2 Temple Enforcer
1 Holy Fire
But, eventually, you'll want to get more rares and epics that I mentioned.
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