I had the same thought about using much larger pieces of fabric for the background around the snowflake itself. If using all the same fabric, I think I would really prefer not to sew endless 2 1/2” squares for the textural effect. That said, I think you could do some very interesting things with the 2 1/2” squares if they were not all the same fabric. Such as a diverse collection of wintery neutrals of about the same value, or inky blues or maybe even forest greens.
And thank you OP for sharing your quilt question. It has offered me a lot of food for thought.