This card can only be used in RDW because of the casting cost.
The +1 is terrible. For RRR, the card should be doing 4-6 dmg not 1.
The -1, while good,
Smoldering Spires does it better as it only costs a virtual R (comes into play tapped).
The -4 seems irrelevant as the earliest it can occur is turn 5 which is too slow. Not that this walker will live that long anyways as it is too fragile.
Abilities I would prefer:
-Sacrifice target creature you control, deal dmg equal to that creature's power to target player.
-Deal 3(4?) dmg to target creature.
-Target creature you control gains haste, destroy it at end of turn.
-Deal X dmg to all creatures without flying.
-Destroy target non-basic land.
etc.