1. Bland level textures which look too computer generated/generic. The best would be probably to replace almost the entire texture library with better looking ones from OGA for example. See Xonotic for much better level textures for example.
2. Bland and desaturated player colors with stick out too little from the background... best solution would be probably to implement a TF2 like "rim-lightning" shader and add some color glow textures to the models.
3. 1st person weapon models... but I guess that is beeing worked on.
Otherwise the game is starting to feel pretty solid
