They pretty much exist to provide big showy overwhelming shows of force as part of the Tarkin doctrine and to piss of the Professional Naval Corps. They know that the Executor and her sisters are too big to be useful; but at the high point of the Empire it's either a big impressive Super-class Star Destroyer or more bloody superweapons.
Just about!
As you say it's very likely given that is kinda the whole point of a dagger shaped hull.
Well yes, if you can reliably point your bow at the target all the time. Which in turn makes some assumptions about maneuver envelope and so on.
[I'm going to try to bring this back down to things that are relevant to SF in general, by the way, not just Star Wars.]
Honestly on a ship the size of a Star Destroyer power generation shouldn't be a limitation for shield power. As for evasive maneuvers... Star Destroyers are always shown as moving very slowly so that's not really a thing.
On the one hand, they're shown moving slowly relative to one another. On the other hand, their combat range and interstellar travel abilities should be pretty impressive.
It's always hard to do a good job comparing what it
looks like spaceships are doing on TV or in a movie when you've got models moving around on a set, versus what they're capable of doing in plot terms. More on that in a bit.
This in itself is assuming that shields are granular like that. The shields could very well be an all or nothing system.
This is definitely something we should keep in mind since Star Trek ships are relatively small so this is a big deal, especially given Escorts explicitly have better dodge chances, but it's not really relevant to my example. Star Destroyers are almost two kilometers long; you're not going to miss one of those.
Yeah, but
the main reactor section on one of the SSDs could easily be a kilometer or two long all by itself. Focused fire is a threat... unless of course shields are all-or-nothing. Thing is, in Star Wars that pretty clearly isn't true ("we've lost our bridge deflector shield!"). In Star Trek the evidence is ambiguous- we have repeated references to degradation of the
forward shields or aft or starboard or whatever shields.
I wouldn't rule out the possibility of localized burnthroughs, at least
narratively, against very large ships in either Trek or Wars, although the combat engine in this particular game doesn't allow for it.
IIRC isn't that exactly what happens when we see a fleet go up against a Cube? The Borg take the fleet about ship by ship.
At Wolf 359, yes. At Sector 001, the Federation ships seem to attack in groups, inflict heavier damage, and last a bit longer (though obviously still taking major losses).
Personally I think that's mainly the difference between good and bad tactics/doctrine.
Wolf 359 looked like what you'd expect from a large number of ships accustomed to operating alone, having all been given the order "attack that cube," with the chain of command consisting of one admiral and a whole lot of captains.
Sector 001 looked more like what you'd expect with ships having been grouped into squadrons, with a clear chain of command from fleet to squadrons to individual ships. And with the officers being given specific training and doctrine for groups of ships of diverse classes working together, with combined arms and mind.
Should note that Star Wars has a very different 'combat scenario' such that I'm unsure if it can be translated to our system in a reasonable way.
Really very critically, their distance of engagement is, well, notoriously small. Like. Really really small. Like, imagine the WWII Pacific Theatre. Now imagine smaller than that.
Trouble is, that conclusion is based on movie visuals where multiple models are placed in the same shot to blaze away at each other. If we apply the same standards to Star Trek we get similar results- ships approach each other to within a few kilometers, so close that you could stand on the hull and hit the other ship with a pistol.
I'd expect combat range to be more or less a wash, since both sides are fighting with beam weapons that are fairly clearly
supposed to be energy weapons going at light speed. You can willfully invent reasons to dial either side's combat range down into the ones or tens of kilometers, but you'd be committing similar abuses against common sense either way.
Incidentally, I wouldn't trust conclusions drawn from visuals of ships interacting in Star Trek for anything other than relative ship sizes, for that reason.