Frankly, I thought BG - the city - was poorly done. The engine doesn't handle big locations very well, and this was particularly bad. The way the sections of the town and buildings were awkwardly split in two on different screens made it somewhat hard to navigate, and it was generally not a comfortable place to explore. The layout was confusing, and I clearly remember feeling the same way upon release - only worse because of the long load times.
Visually, it was fine and all, but I hate this kind of splitting up.
The same was true for Vegas in Fallout NV. Really annoying.
The odd splitting was incredibly awkward, especially when there was a wall splitting the map into two halves. I had to visit almost every area of the city yesterday to find the right spot to get me on the north side of one wall. Even ones that logically should have worked didn't.
It looks like the whole place was drawn at once, then split up later without any thought into how it would work. One temple is split in half in a way that doesn't work on either map, so they just didn't bother populating it. They never did get the hang of how to work with maps in the Infinity Engine. BG2, IWD, and Torment all had problems and areas the pathfinding just couldn't handle, but I don't think I can remember anything being quite as awkward as these splits were.
And I'm with you on New Vegas, especially given how incredibly empty and pointless most of those areas were.