Old Org was a bit of a mess but it was great as you still had to navigate around the town before everything was centralized, Stormwind didn't change to much except we lost the Park which was a big hit to RPers on my server.

As for the casualization, it wasn't the leveling that was the problem it was the fact that everything felt way to easy and dumbed down, there used to be a huge sense of achievement when you did things, splitting raiding between normal/heroic also diminished the prestige of raiding, in WOTLK the 10/25 change was perfect and the hard mode raiding made another level of prestige available.

Sadly It just got worse after Cata and didn't really get fixed til legion.