Does the +1 stack, IE you move it again and it gains another one? Or is it static?
The + 1 stacks permanently.
So it goes +1, +1, +1, and so on? That might get out of hand, esp. with the upgraded, but then again, it is an activated ability so that might counter balance it. Also rampant creature playing would, or cards that spawn other cards.
That being said, however, the ability looks nice. You may want to start off Bishop with 0_1, so that it doesn't attack straightaway and start gaining attack. Also to reduce the effectiveness of epinephrine on top of this; move bishop ONCE and it gets a massive boost.