The armament is different but no matter. I can't see what you mean by similarity with the RAS. They look different, only about the same size.
Anyway, there is more then superficial from the VSD to ISD. Performance and usefulness is also different.
You're looking at it the wrong way.
It DOES matter if it is redesigned. You cannot take an already existing vehicle, one who has a particular name and has been seen in many games and just change it.
The poll says it all.