The main thing that I dislike about making exclusive things open to everyone is that it doesn't always make sense from an inRP perspective, given that a lot of unique ships are commissioned only once by individual parties. I actually feel more like effects and the like should be the things that are less exclusive, because they tend to represent technology that could feasibly be replicated elsewhere. Meanwhile, unique ships are engineering projects that have to be undertaken with a lot of different factors considered that are harder to replicate on a mass scale, particularly given that mass production requires unique infrastructure.
On topic with the OP, I am not at all biased in this of course, being both a modeler and a person who wants a unique ship.