Unless you go through the trouble of specifically placing more +1/+1 counters on her through different means, Arcee, Acrobatic Coupe will always only be a 3/3, while Arcee, Sharpshooter will likely only deal 1 damage each activation
Also, we should be prepared to either remove it ourselves if it's hurting us, or to have it stay in play for multiple turns without falling too far behind
Thrun, Breaker of Silence is a solid midrange creature to apply pressure on your opponents
That deck can be a conversation piece when you sit down at the local game store
[c]Animar, Soul of Elements[/c] (Protection Blue/Red/Green Creature) An astonishingly good commander, [c]Animar, Soul of Elements[/c] is what you play when you want to play creatures
Also goes into Shaman tribal