Hearthpwn

Malygos and Dalaran Aspirant exist but they are some what conditional.

If you're asking "Can they just put a +2 Spellpower minion in the game" the answer is assuredly "yes" as there's already a) a minion with +5 and b) there's a minion with theoretically +2 (+) Spell Power. The real question is "What would that be worth stat wise and how could it be implemented as balance."

Spellpower is one of the harder keywords to definie in terms of mana value as it's not as static as "Taunt" or "Windfury" or "Charge". One could make the argument that +1 Spellpower appears to be worth ~ 1 stat point - i.e. Kobold Geomancer versus the variety of vanilla 2/3 and 3/2 for 2 mana, and Ogre Magi compared to Chillwind Yeti. The problem is that +2 would likely be worth more than 2 stats though as the potential snowball effect of +2 Spellpower compared to +1 isn't really the 1:1 comparison it might appear to be.  In other words, I don't think you could say 4 mana 3/4 +2 Spellpower is fair even though that's -2 stats compared to accepted vanilla baseline for 4 mana.