No, I think this is fine. If a 1/1 haste, first strike creature costs 1R, then having two opposing colours as the mana cost is worthy of a 2/2 haste, first strike. It's good, but certainly not
too good. It's as good as Goblin Berserker (which never sees play). If you want proof that a creature can move from costing


to costing


fairly, look at Shock Troops and Goblin Legionnaire. They're not identical, but they're very close.