One way to look at it is to put the broad array of Star Fleet Universe ship designs into three categories.
Category 1 would be the "source material" ships; those which are more or less directly connected to either the original or animated series, or which were "Franz Joseph" hulls laid out in the
Star Fleet Technical Manual.
Those are the ones which would have the strongest impetus behind trying to keep them accurate to the source material; but it is worth bearing in mind that even these ships have something of an "out" thanks to the refits installed in the versions you see in the Main Era.
(These refits not only allow the miniatures to be given a somewhat different look here and there if necessary, but I suppose might also allow a later set of releases designed to cover the "pre-refit" versions as they had served in the Middle Years. The Fed DNG is a prime example; the current Starline 2500 model has a different secondary hull to the Franz Joseph original, but one could easily envision a more FJ-accurate version done for a would-be 2500-series edition of Starline 2400's
Squadron Box #91.)
Category 2 would be those "home-grown" hull types done for either one of the "TV empires", or for those SFU-native powers which have gained the most traction over the years (such as the Lyrans and Hydrans); essentially, the kind of ships which have already been ported over into
Federation Commander (where they would have "new" art drawn up in order to support that game).
Many of those ships have had art done for them, from basic line art seen in some of the
SFB rulebooks (or used for the Ship Cards in
FC) to 2D and 3D art cooked up by the likes of Adam Turner, Xander Fulton, and others. (Much of Adam's 3D art has been used in the
FC and
Starmada rulebooks, as well as for the covers of the various Booster Packs and Starline 2400 Squadron Boxes.)
As Rambler noted, one or two of these designs have been "fixed" over time; both the Fed OCL and NCL had their engine configurations re-worked at one point, though even in those cases the fixes have been in play for a number of years already.
Category 3 would be the vast selection of ships from earlier (or later) time periods, such as the Early Years or the X-tech era; or from the more distant regions of the setting beyond the Alpha Octant, which have basic layouts in SSD form but which, for the most part, have yet to be given more elaborate artwork (or perhaps, don't have the same accumulated momentum of support behind such art).
In my view (such as it is), it is here where the largest scope for change would be found; or, to put it another way, the largest scope for what in most cases would be the first true imagining of many of these ships (or entire empires) in a Starline 2500 context.
But that, of course, depends on what state
A Call to Arms: Star Fleet would be in by the time Mongoose might consider taking on some of these alternate settings.
