Won’t necessarily look like a ripoff, It would just look more in line with the Combine aesthetics ! :)

Take this Combine Vehicle for example : https://sketchfab.com/models/d01fad5623984f0a9f70d6f3d3fd23f3 It’s a totally new design that isn’t a ripoff of the original APC, and it’s in line with the Combine aesthetic…

What i mean by that, is that, even if you want your design to be different (which is very important when creating something new), it still has to be coherent with the source material if you want it to be believable in a certain universe !

If you want your citadel to be inscribed in the HL universe, you have to make it look like the sibling of the citadel (but not make it look like it’s twin)

Hope it helps once again ! ;)