2 5 damage cards for 2 mana ( mage has 6 dmg for 8?)
Mind Blast targets ONLY the enemy hero, and cannot be used to remove minions, so it cannot be compared to Fireball in anyway shape or form. Other than that, Fireball does not cost 8 mana.
2 cards that deal 5 dmg to anything and heal your hero 5
Yup, and based on other cards, it's budgeted correctly at 6 mana cost.
2 mind control
Undoubtedly strong cards, but nowhere near as broken as a lot make it out to be, can be worked around with smart deck building and, crucially, smart play, and is getting nerfed anyway.
2 destroy any card 3 dmg and under,
2 cards destroy any card 5 dmg and over,
The Shadow Word cards are basically any other classes hard removal, split into two that cover certain, non-overlapping ranges of minions, one has a very narrow period of play, and they also have a potentially crippling blind spot. SW:D could perhaps use it's mana cost tweaking upwards some, but other than that, they're fine.
2 cards that boost your minion health 2 and draw a card for 1 mana
Yeah it's potentially strong, but they are generally used on minions with passives, such as NSC, or Taunts, which means that that minion becomes even more susceptible to silence, and if you do silence it off, you've got an even more efficient trade.
2 cards that double minion health
2 cards that make your minion atk = to its hp
These are pretty much only used in combination, and the combo is gimmicky at best, with decks built around them being subpar and only playable if either (a) you're really lucky and pull all the correct cards out, or (b) you're playing against scrub. Given how many cards you have to pump into a minion for this combo to work, it also means, much like PW:S, that it is incredibly susceptible to silence, and one single silence can basically ruin any potential a Priest buff deck has.
2 cards that are 1/3 and let you draw whenever a minion is healed and only costs 1 mana
Budgeted the same as other, comparable class specific 1 drop 1/3s, the effect is not even guaranteed to go off, the minion can be cleared out without too much trouble, and it's a 1 drop that needs to be saved to mid game to be of any reliable use.
2 cards that heal all your characters and deal 2 dmg to all other characters (again costing nearly s little as an arcane explosion)
Arcane Explosion costs 2 mana, Holy Nova costs 5, so no, it does not cost "nearly as little". Arcane Explosion also synergises with mage decks, as they tend to run with more +SD minions than Priests; Holy Nova's synergy lies in the heal aspect for Priests. It is a strong AoE clear, it is in no way a broken AoE clear.
2 cards that silence all enemy minons for 4 mana (great for those players using lots of taunts and boosts
Barely anyone runs this, because a 4 cost card that gives no tempo boost and not much control boost is difficult to play. You'll see the odd one, but mostly for the card draw on top of the silence, or for the rare occasion when an enemy spams taunt and boosted minions.
2 cards that come out 5/5 for 4 mana and the more you boost their hp the higher their attack gets too
Oh look, drop a silence on them, and they are worthless. Or, you can chip away at them with your disposable minions, and, would you look at that, their attack drops as their health does too! Amazing, that is.
2 free silences
Very niche card, and in most situations, an owl/spellbreaker will be better because it gives you a minion, and thus more board control, at the same time. The only time silence is better is when you want to play it in a round where you don't have enough mana for the other 2.
2 6/6/6 and + 3 minion hp
Decent minion, not overly strong, but solid enough. Budgeted exactly the same as Shaman Fire Elemental, with the +3 HP replacing the 3 free damage (which is almost always more beneficial).
Basically, what I'm saying here is: you're talking out of your backside, and (purposefully?) twisting or flat out misrepresenting cards to make them sound stronger than they are/their counterparts weaker than they are.