I'm in total agreement with the opinion that the shockvalue of seeing the destroyed fleet would be diminished if we saw the battle.
The breakup of the transmission from Admiral Hasnon (sp) lets us know that things are not going well. Then to later see the D fly through the wrecked hulls and debris lets you know this there was a total massacre.
At that time it was truly impressive as we never saw more than 4 or 5 ships on screen at a time. To see all of these starships we'd come to view as somewhat indestructible in that condition was hard to believe. It made me wonder how many ships Starfleet actually had left.
While cool to watch, DS9's dominion war VFX sequences made it look like an assembly line was spitting out an endless supply of starships.