To be fair I would imagine Kerberos already looked into that - I was trying to establish if this was speculation or if you had done a study. This would seem to be pure speculation without evidence - Technical requirements does not match the coding requirements.
Of course it's only speculation but I don't need to do a study in order to make a broad comment on the bigger picture. Kerberos might have had a very good reason to build an engine from scratch, but I find it very hard to see what it was. If anyone has any knowledge on this subject I would be happy to hear.
I don't know what you mean by technical requirements vs coding requirements. I'm getting the impression that you are not able to or not willing to try and understand what I'm saying, which is a broad assertion.
I have never come across a FPS which deals with as many possible combinations of ship sections (cruiser/dread/lv), weapons (small, medium,large, extra large turrets and fixed) and the accuracy to target and destroy individual components (blow off enemy turrets) - that level of complexity, across 6 different races each with their own travel method - would seem in excess of the FPS engines abilities I've played that let you go across a free movement environment.
What you are saying here tells me that you have very little knowledge of what I'm speaking about and that you (again) did not understand what I'm saying. What you perceive as an FPS in abstract terms isn't fundamentally different to the 3D battles in Sots. Different ship sections are not different to an FPS character holding a different gun, it's just several different meshes grouped together. The actual skill required is in the graphics, not the coding (i.e building the different ship sections in such a way that they can always be put together and still look nice).
To achieve individual hits you analyse the ship component before hand, either manually (artist who built the component defines locations) or automatically (write a tool that "compiles" the component as part of the build process). The end result in either case is the same - different locations around the centre of the ship correspond to different ship systems. This can be represented as meshes or primitives, either way something that can participate in collision detection. The data structure to hold this connection is a simple map. When a hit occurs it will have a location relative to the centre of the ship and correspond to one of these predefined components. This is something basic that the physics simulation provides. With that coordinate relative to the ship centre you look up the ship system in the above date structure.
All of this can be built around the what a basic engine would provide, and an FPS engine. What happens when a hit is scored and how you process that is irrelevant. The engine just wants to have objects, render them, move them, perform physics simulation, and then hand over control to your game logic which may result in some objects remove/added/modified or your internal data structures changed. It doesn't care.
The number of components, races and so on is completely irrelevant, that is a question of game content - art and design. Adding another 10 races to the game would have added relatively little coding to game logic and no code to the graphics engine. The different travel methods affect mostly the strategic game logic, they have almost no effect on the battles other than slightly different physics properties of ships.
I'm going to "speculate" again and say that you don't like what I have to say but you have very little knowledge in this area and you don't really understand what I'm talking about. I suggest you take a deep breath and simply say what really is on your mind rather than trying to dig deep into technical details in something you don't really understand.