Lacks something, it feels a bit too simple

Also you really need to those down the primary colors, they seem saturated...
TF2 uses muted/pastel colors and not in-your-face color pallets

It's a nice theme and color! I'd just add a phong mask which would greatly help visualize the texture of the paint, and as someone who likes doing pink-ish war paints i know how it can be annoying to make a matching blu version that looks fine, It'd be recommended to lower the saturation on Blu, and perhaps brighten it a bit.
And don't be scared to explore the theme more, since its based on sakura, maybe a more deliberately wooden texture would help it pop out above the rest