Hey, I can’t let the E-D go down without a fight. So here I go, looking at the Technical Manual for the 1701-D.
Phasers- Let’s see, each individual emitter on the E-D can direct 5.1 megawatts of power. There are 12 such structures on the ship (with the groups in Saucer Dorsal and ventral sides, the Battle Section with a ventral array and an aft array, and both nacelles having arrays). Looking at the breakdowns, the most it could fire at one time into one target area would be about 12 arrays (with a side long shot)…so about 60 megawatts converging onto a point about 2 X 3 meters for maximum of about 245 seconds of continuous fire before overheating problems would cause significant loss of phaser systems.
However, phaser disperse rapidly in warp and or deflector fields… so the range would be close. Big ouch once the shields go down on the E-D. So I would say that given the 360 degree nature of all the phaser emmitters, they would be used to pop all of the fighters and auxilary craft into oblivion.
Photon Torpedoes- Looong range on these suckers. 3,500,000 kilometers for midsize tactical yield (apparently, the closer you are to the firing vessal, the bigger the BOOM). Explosive yield is around 1x10^3 megajoules. These torps are supposedly the second generation and are much higher yield than any employed previously. (shrug)
Numbers of torpedoes on board: about 200 that can be used as weapons (60 odd more for probe use and such). They can be fired from the front and rear launchers in groups of 10, with a reload rate of about 2 seconds for each group of four. So…in less than 2 minutes the E-D could shoot off all 200 of its torpedoes, with a big initial wollop of 20 torps at once. Even an ISD would wince at that.
Shields- Such a sticky point. Hmmm…says that battle shields can dissipate energy at the rate of 7.3x10^5 kW per 170 milliseconds with 65% of the shield still working after 24 hours of continuous use. Or, the E-D can take its own phaser barrage for about 3-4 hours before the shields could no longer take it.
As for fighters and such bouncing off of it, they would. But the way the manual explains it, the fighter would be intact and the pilot a bit confused as to how the E-D teleported away (the shields make use of micro-warps to help move matter, so it appears to them that the E-D teleported).
So my opinion: The E-D would analyze how to stop the ISD in space…Get beat-up using phasers to try and slowdown the armored behemoth that the ISD is…then whack the hell out of the ISD with torpedoes.
Lots of explosions, pretty special fx’s, and a draw. The ISD is immobilized, but the E-D won’t be able to get in close enough to finish it and any boarding parties transported over would be slaughtered.
Now a funnier scenario dawns with the approach of a borg cube…