I think forcefield is on another level and not really comparable. I'll write down my reasoning here, comparing the cards with barkskin. Since BM-only, upkeep +2 and cantrip are all the same, I'll completely exclude them and assume that barkskin is balanced.
[mwcard=DNE01]
Barkskin[/mwcard] is essentially a [mwcard=MW1E36]Rhino Hide[/mwcard] (5 mana) and a [mwcard=MW1E32]Regrowth[/mwcard] (6 mana) combined in one card. Since you save a quick cast I'll rate the cost 1 mana higher.
Barkskin costs: 5 + 6 + 1 = 12 and this equals 4 + 2 upkeep (apparantly)
Transmutations The cat combines a [mwcard=MW1E28]Mongoose Agility[/mwcard] (
5 mana) with a weakened version of [mwcard=MWSTX2FFE06]Lion Savagery[/mwcard] (5-1 =
4 mana) +
1 mana for the quick cast. I rate the subtype gaining at
3 mana since it "only" gives the ability to gain buffs but not buffs itself +
1 mana for the quick cast.
The wolf combines a weakened version of [mwcard=MW1E01]Bear Strength[/mwcard] (5-1 =
4 mana) and a weakened version of [mwcard=MW1E36]Rhino Hide[/mwcard] (5-1 =
4 mana) +
1 mana for the quick cast. . I rate the subtype gaining at
4 mana because I think that canine subtype is a little better than cat +
1 mana for the quick cast.
Total cat: 5+4+1+3+1 = 14 = 12 + 2 = Barkskin + 2
Total wolf: 4+4+1+4+1 = 14 = 12 + 2 = Barkskin +2
I agree that a reveal cost of 3 is still too low and I will change it.
But I would rate it at 4 now and not 5 + keeping the cantrip. Do you agree or do you think I undercost something or make a wrong reasoning?