Well, against level 3 you won't need CC (creature control) like the fire shield or too many fire bolts... And as the phoenixes can revive, you could add a couple of immolations and sparks (to immolate or make a finish blow)... I personally like minor phoenixes (upgraded), since you could use them with fractal to make an awesome deck... Here it is Fractix (fractal phoenix) with only upgraded phoenixes:
5f0 5f0 5f0 5f0 5f0 5f9 5f9 5f9 5f9 5f9 5f9 61o 61o 61o 61o 61o 61o 61o 61t 61t 622 622 622 622 7ds 7ds 7ds 7ds 7ds 7ds
A great deck... You can also try others, but if you want an upgrade path for THIS one, I recommend not upgrading phoenixes, since they reduce their attack, and you are short in creatures