Heh, well, I've said it before and I'll say it again, there was no acting in the prequels to match Lukes final face-off with his father, Anakins battle with the dark side was little more than a token resistance compared to Luke, and when he turned for a moment, you could be easily convinced that not Vader, Windu or anyone could have stopped him.
I agree that the combat from the original series was better, at least in the ROTJ, more using the sabre as a weapon, less using it as a Nightclub dance-stick. And even the space combat had things called 'characters' whose progress you could follow, and the battle wasn't so frantic that you couldn't actually tell how it was going or, indeed, who was shooting at whom. Maybe not as realistic or chaotic as a real battle, but it's a
story (or, at least, was supposed to be). Not to mention the fact that the Battle of Endor was carried through stupendously using 4 different sets of characters in different locations (Lando, Han etc, Luke, Admiral Ackbar), remember, 50% of those characters weren't even around in the first film. That's the importance of putting weight on the characters and plot, instead of the special effects.
That was the thing about TOS, things felt 'real' the Falcon was beaten up and grimy, even the X-wings had much from the exhaust ports on them etc, whereas everything seemed too shiny in the prequels. At the end of the day, it felt like I was watching 3 rolling promos for Industrial Light and Magic

In fact, I was almost half-expecting Buzz Lightyear to show up at some point :/