To me scale is a virtue, but just one of many. It's good to have a fixed scale where possible. And some times it's not. In xwing it is, and that is great. In a SW cap ship game it isn't, at least not if you want ISDs and corellion corvettes in the same game
But more than physical scale, game mechanics scale is important. More important than physical scale.
The big issue with an ISD in X-Wing isn't necessarily the physical size, but the mechanical scale that couldn't fit into the game.
Long story short, scale is wonderful when possible. In armada it is not, so there would be little point in getting worked up over it. But even if the physical scale slides, mechanical scale should be maintained.