My guess is that space combat in Star Trek Online will fall somewhere between the two extremes of hyper-realism and conventional MMOG gameplay.
I'm pretty sure it won't be a first-look, over-the-horizon kill kind of situation, which is the reality of combat today (and the likely reality of future combat). While that's realistic in terms of how technologically advanced naval warfare is conducted today, it probably wouldn't be much fun as a model for gameplay in the Star Trek universe. But I also suspect that space combat in ST:O won't be just a dumb, press-F4-till-your-fingers-bleed kind of thing, either.
What I hope to see are space engagements designed to typically last several minutes for starships. (Engagements between shuttles/runabouts and fighters might be faster.) I'm thinking about 2-3 minutes for frigates and around 5 minutes for the biggest player ships sounds about right, since starships -- with their many internal systems -- should be capable of collecting tactical intel, maneuvering, establishing the correct defenses, performing real-time damage control on key systems, and firing the appropriate weapons. Not only are all those things appropriate for a massive space-faring vehicle, they're strongly representative of the kinds of things we've seen starships do in Star Trek.
A pacing for the typical space combat of a few minutes would, I think, occupy the happy middle ground between one-shot-kill (unfair and thus not-fun) and spam-your-special-attack fistfights (boring and thus not-fun).
Perpetual seemed to be heading in this direction in their design. Here's hoping whoever follows them comes to the same conclusion: space combat should last long enough to constitute interesting tactical gameplay.