Shooting Star - a bit more consistent to have in the arsenal over Arcane Explosion.
Frost Nova - changed to reduce the survivability for Mage, but the new one has more payoff for the commitment of freezing your opponent's board in form of card draw.
Kabal Lackey - added as part of my revisory to my Core Set, where I increase the Classic Set to 16 cards and add necessary changes. Lackey replaced Kirin Tor Mage, because while that card was better for agressive Secret decks and provided a safer discount for them, agression isn't something this class has, so it made more sense to add a slightly weaker unit that can allow for more interesting Secret play. Also, he helps Aegwynn becoming better.
Sorcerer's Apprentice - the highlight of the changes. Replacing it with an entirely new card would still cause too much problems for Wild, so I instead opted to change her into a 1-drop to relive the days of Tempo Mage again and keep it in check. She has created some of the most uninteractive stuff over the years, and while she can still reduce the cost of spells, it's no longer applied on all spells after the first one.
Snap Freeze - it's a better card than Shatter, and that card was a close candidate to be included in the Core Sets. It's for you, Ben Brode. And for some Freeze synergy users.
Scorching Wave - added as part of my revisory to my Core Set, where I increase the Classic Set to 16 cards and add necessary changes. A new control tool. It does some nice damage to a minion, but the real value is in the upgraded damage on your Hero Power. With future expansions, this card can give those Hero Power-related cards some more oomph.
Arcane Breath - added as part of my revisory to my Core Set, where I increase the Classic Set to 16 cards and add necessary changes. This addition further strengthens future Dragon-based Mage decks.
Mana Bind -another hightlight of this set. Counterspell has been toxic throughout it's existence, creting so many unfun moments. This one will serve similar purpose without pointing a middle finger.
Frosty Fausting - a nice stalling tool for any deck that aims to draw a lot of cards. Gadgetzan Auctioneer just got a cold friend to be supported alongside. Note that it won't Freeze enemies that are already frozen.
Apexis Smuggler - a better Secret synergy card, giving you a lot of card generation.
Magna Aegwynn - the pinnacle of card generation. You can reuse a lot of your spells, and with some cost reduction, you can get even more. Also has fun synergy with Snap Freeze.