Green really should have solid beater creatures. However, (mechanics speaking) they typically don't. Trample just isn't useful on early creatures, and on later creatures there are often bigger concerns. However, (thematically speaking) they shouldn't be total aggro like red, but they should have some way to persist as threats.
So I've suggested a new mechanic for Green creatures.
Forestcover - (If ~this~ has Forestcover, ~this~ cannot be the target of spells or abilities. Whenever a permanent you control becomes the target of a spell or ability, ~this~ loses Forestcover and gains "whenever ~this~ becomes the target of a spell or ability sacrifice ~this~" for the turn.)
The flavor of the idea is that they are hiding in the Forest and hence you cannot target them. Targeting something else essentially will "blow their cover" for the turn and in this state of surprise they are more vulnerable.
A little sub-power within Forestcover is that when cover is blown they have other effects. Flavor-wise the idea of the creature abandoning it's cover for some reason, or realizing it's blown and being more aggressive in some way.
Sample creature:
Lurking Troll
Creature - Troll
Forestcover
If ~this~ does not have Forestcover, ~this~ gains 2G: ~this gains +2/+2, trample, and "sacrifice this creature at the end of your turn."
2/2
Thoughts?
