I wasn't into Magic was the original Ravnica came out, so I can't see what everyone's so excited about. I mean, like literally everyone on the official forums were crying and wailing for a Return to Ravnica without end, so I'm sure it must be awesome, but from what I can see it was just a bunch of warring guilds and multicolored cards.
I think it has a lot to do with the tournament environment, which I personally couldn't care less about.
It was the set that came in after Mirrodin rotated out, and so Standard suddenly lost the ridiculous nastiness of Affinity, (which was dominating the tournament scene) while gaining a bunch of cards that were far less overspecialized and underpowered than the Kamigawa block that had immediately followed Mirrodin. So, we got a more diverse metagame and decent power creep, which folks associate with Ravnica itself rather than its placement.
In Ravnica's defense, though, it also introduced hybrid mana, (which allowed for multicolored cards that were actually easier to cast) as well as greatly enabling tri-colored decks, which would then be supported by at least three different guilds' mechanics. Each guild felt different, and had at least one fun legend running around in it. (Yes, each guild had two legends, but a lot of the secondaries were just 2/2s that did minor things when you cast spells in their colors. Decent, yes. Interesting? Less so.)
tl;dr = I liked Ravnica, but don't think it
quite deserves the hype. I'm still looking forward to it, but not enough to say "Screw Avacyn Restored! Fast forward 5 months NAOW!" like a lot of folks seem to be doing. Angels vs. Demons 2.0 looks like it'll be fun too, y'know.