What changed

[Photon]

Notice that during the ship-to-ship battles in TOS and TNG, many times the losers ship were not blown up but left adrift w/battle scars and plenty of damage.

This didn't happen that much in DS9 and Voyager, as most losers got blown up. I do recall in Sac of Angels (i blv) that some of the ships were being tractored that received battle damage, but for the most part ships were lost.

Khan vs Kirk, both ships took it in on the chin-even w/shields down. In DS9 or Voyager, a ship w/shields down is a sitting duck for destruction. Perhaps weapons are stronger or hulls/shields weaker I don't know.

 

[Jono]

I've never noticed a stark difference but I'd put it down to a budget issue, it is expensive to blow up models. Move to CGI and you can blow up any many ships as you want since they are just 1 and 0s.

As for Khan and Kirk in STII, that was for plot reasons as well or it would be a very short movie. Plus if I remember correctly in their first engagement Khan was trying to cripple the Enterprise rather than destroy it outright and Kirk then just tried to give his damaged ship some breathing room. In the battle in the nebula the Enterprise dispatches the Reliant with ease.

 

[Disillusioned]

Something I hated about the war was that the ships seemed to have lost their shields, despite dialog indicating that they still had them. Ships seemed to take damage and get destroyed far too easily.