Although if you ever want to animate the vehicle turning, it might be best to have some sort of axle going on.
I agree with both of you about the axle and the underside in general, but I'll also caveat with these are far from finished models. The wheels need some sort of "inside," as the hubs are basically hollow and there is no drive train (the whole vehicle underside is blank). The vehicle body model topology (meaning the polygon mesh) needs to be rebuilt if the model is going to see long-term use. And since the model's mesh needs rework, the texture itself is also pretty temporary. I suppose, more than anything, these are mostly just proofs of concept and for us to banter about...so I appreciate the feedback. Keep it coming!
I also agree that the APC look isn't a "bad thing," but it would make more sense if there was a door on the pack (for people to get in an out). Obviously there's no need, since it's unmanned. I know there's the "emergency cockpit" part, but seems like that would be a smaller door since it's more of a "just in case." Also, I think rounding out the back a bit will bring it into style with the rest of the body. I haven't done that yet, but probably will just to see how it looks.
I like how you moved the wheels slightly under the body. It's cool, and makes it look more like a military vehicle.
Yes, that was my thought as well. Although as I've been playing with the v4 model, I also went back to look at more in-game screenshots. I'm starting to think that an even beefier variant of the v4 model will probably be more like a panther. So I'm rethinking about how a lynx and panther might actually look against each other. Possibly a stripped down/smaller version for a lynx (maybe two wheel), and a bigger/armored v5 for a panther.
You mentioned the difference between tangent space and object space. Could you provide an example of where the two might be useful?
To be honest, I don't really have a good idea of what an object-space normal map would be useful for. Possibly if the objects are stationary but the light is moving. But in that case, a tangent-space map would also work just fine. Maybe that's something I should look into, in case I'm missing something.