See, you're all very apologetic to it because of nostalgia. But I didn't grow up with it (I didn't watch DW until recently, actually), so that lens is of no use to me.
I didn't see it until 2013. I only got into Doctor Who in a big way a few months before its 50th anniversary, so it isn't nostalgia for me, I just like the story
So, as mentioned, overrated fluff. Not bad, mind you - but not the classic its made out to be. Without Davison, Pertwee and Troughton, it'd be totally worthless.
To
you its overrated fluff, to others its an enjoyable story. Also, yes, without the three main characters, the story would be totally worthless. I would have thought that a multi Doctor story without Doctors would be pretty obviously worthless if it didn't star the Doctors

Although, to be fair, the replacement 1st Doctor was very good. Not quite Hartnell, but no one could be Hartnell but the man him self. The replacement probably did the best job anyone could (although the guy from
An Adenture in Time and Space seemed like he could have nailed it, too).
Anyway, on to what I've seen. I got the Doctor Who Revisited: 5-8 set yesterday, and I saw
Earthshock for the first time. I went with the 4 part episode version, since I've read that the "feature length" version on the DVD (that puts the episodes together into one long video with no beginning and endings in the middle) has pretty bad video quality. The 4 episode version is just as good as you're going to get, though (its just taken from the Earthshock DVD itself).
The story was enjoyable, with the Cybermen being an interesting villain and the overall story done well. I'd never seen an episode with Adric, so its funny this was my first. He was a bit obnxious, but not terrible (I wasn't cheering for his final fate or anything). It was also my first episode with Nyssa, and honestly I think I like her better than Tegan, who I've seen before but never really made an impression.
I've long been spoilered to the ending, but it was done very well, and I like that it was literally pointless, sometimes people just go out without accomplishing much of anything. Playing the credits completely silently was a great touch, and really made the ending even more intense. Overall, this was a fine serial, although I haven't seen enough of the 5th Doctor's stuff to really rank it or anything.