I know STO has its current visual style pretty well established and unless a engine overhaul is done can't really adapt to some of the more critical things I would like to see changed. However, there are a great many smaller, more detail oriented elements (as well as a few perhaps larger ones) that could help with overall immersion. I also imagine many of the things I have as feedback may have been considered and disregarded but I do feel that these things can and should be addressed/reexamined.
Adjust planet and solar dimensions to match a more realistic representation of scale.
Revise solar effects and bloom; no one looks at a star and always has a UV filter on their eyes, EVE Online has this down pat (much like the planetary scale issue)
Increase texture resolution at the higher end of the graphical scale to allow for finer ship paneling and character clothing detail; with graphics cards getting better and other MMO's getting more and more detailed it would be great if the upper range of settings reflected this mentality and visual shift.
Like the proposed color style options for the new LCARS UI in game, allow a user to select more accurate font styles and scale the UI accordingly (Allow usage of Helvetica Neue Bold Ultra Condensed - All Caps; for Fed as an example). Note that this would NOT be a default setting. Condensed fonts have readability issues so it would only for those that really want it.
If texture resolution is increased detail clean up for ship textures such as the exposed component texture on Intrepid class and Nova class, among many other things.
Hopefully all of these won't get shot down but I felt it should be said. I am quite open for critique or addition to this list.