Okay, oaky...before I get attacked by all, please hear me out!
Yes, I know that the album was almost as huge as its predecessor and still is a 'fan' favourite (especially for those 'fans' who don't know of the existence of any other Floyd albums). But IMHO, there's very little about the album that allows us to regard it on the same level:

'Shine On You Crazy Diamond' - the first parts of the song might be one of the most evident epitomes of 'gorgeous beauty' in rock: Gilmour's calculated, but nevertheless inspired guitar notes playing over the moody synth backing perfectly convey the feeling of majesty, sadness and inescapable tragedy that the song's all about. However, the song ends in a rather feeble saxophone solo, and then off we go into loads of moody and atmospheric garbage.
Honestly, I don't know how anybody can love 'Welcome To The Machine' and 'Have A Cigar', two of Waters' worst anti-establishment anthems. The whole song is built on dirty electronic gadgets that totally eliminate any therapeutic feelings you could have generated during 'Shine On'.
As for 'Have A Cigar' that's sung by Roy Harper because Dave didn't want to sing it since he didn't like the lyrics (he had a point, too), it's probably okay by any average band standards, but consider it a Pink Floyd highlight? It's just a mid-tempo bluesy tune with nothing that stands out - just your standard rhythm, drums and singing. Kinda like the Gilmour-sung part of 'Time', only weaker because Harper just isn't that expressive, and the lyrics kinda suck.
That leaves us with 'Wish You Were Here' which is also gruesomely overrated as a song. I used to think this was my all-time fave Floyd song when I was younger – but time has a great way of making you look at things differently as you get older. Yes, it's good, but how come it deserves its reputation of one of Floyd's best songs? I could name at least four or five early Waters acoustic tunes that aren't any worse! Maybe it's because of the pretentious lyrics?
Finally, we reprise 'Shine On You Crazy Diamond, Pt 2', and the final parts are also much weaker than the intro.
I mean, c'mon, it ain't an unworthy album. But there's an interesting thing that you may discover if you listen to all Floyd albums in chronological order: Wish You Were Here is the first album that shows genuine signs of 'regression', in the sense of 'going backwards', not necessarily 'worsening'. They reached their zenith on Dark Side Of The Moon and just couldn't go any further: neither Gilmour nor Wright were able to contribute many new musical or conceptual ideas. So this album, wrought and produced with so much pain and tension over the course of two years, is a stalemate. Curiously enough, it's much more close in sound to Meddle than to anything after it:
1 - the main theme of 'Shine On' creates the same mood and has almost the same melody as the main theme on 'Echoes'
2 – 'Have A Cigar' sounds just like the part I called 'boring blues jam' on same 'Echoes'
3 – 'Shine On, pt VI' recreates the bass thumping and dentistry soloing of 'One Of These Days';
4 - isn't it possible to trace 'Wish You Were Here' to some of the folkish songs on that one, like 'Fearless'? Yep. I think it is...

CONCLUSION:
Wish You Were Here is but a slightly more sophisticated re-write of Meddle with a lot less innovation (if any) and a lot more pretentiousness and preachiness. A bizarre collection of aimless jams interspersed with revelational moments of beauty on occasion.

(**Have you ever wondered why this was the last album with any significant contributions by Gilmour and Wright, with Roger stepping in and taking full control over everything after that? No? Because they were exhausted. If Roger had been able to gain total control over the band five years earlier, he'd have done that. He wasn't, because there were lots of ideas in these two pots. This album amply demonstrates that Roger was the only guy with something left to say…