Do you mean bolt shooters? I don't have a problem identifying them and wont change it and I cant make them bigger.
You can change any texture yourself. The hardest part is finding it by searching through your installation directory. After that you can copy it to the equivalent path in your copy of my mod.
The bolt shooters don't look as intimidating as they are harmful tough. The bolts them self are hard to see. They are small, fast and travel far. The romans got a different model, so you would need to change them too.
If you would make the bolts (not the bolt shooters) red like the star wars laser blasters (or just a bit in that direction) i would include it in my mod.
Maybe i'll do that in time if i am bored, which wont happen anytime soon.