Actually there is an opinion in the Mishna, Beit Shammai, that says that the blessing should be “he who created the illumination of fire.” The version that we use is that of Beit Hillel.

The Talmud explains that the plural “illuminations” alludes to the various colors of fire. —Berachot 51b and 52b.

(In the Rebbe’s Haggadah the colors are described as red and green. Rashi writes “red, white and green.” Tikunei Zohar (tikkun 21, referred to in the Rebbe’s Haggadah) writes that there are five colors: white, red, green, black and blue.)

The Vilna Gaon suggests that according to Beit Shammai we bless G‑d for creating the original element of fire, which is only one color. That’s why in Beit Shammai’s version it is “who created” in the past tense, referring to the past event when G‑d created the element of fire.

According to Beit Hillel, on the other hand, the blessing refers to the fires that are constantly created and are multi-colored. That’s why Beit Hillel’s version has “who creates” in the present tense.

(It has been suggested that one of the recurring themes in the many arguments of Beit Shammai and Beit Hillel is whether to grant significance to the potential (in this case the original element of fire which is the potential for all fire) or to the actual.)