You're still supposed to drive around the circle though, right? Or am I misunderstanding?
That intersection you showed is clearly big enough. This one doesn't look big enough. Or is it? There are smaller intersections than this one, also. (And I realized that this one might be a bad example because it's not four directions.)
At some intersections in the UK, the roundabout is literally a small circle of paint. The car doesn't really go "around" it because it's so small. It mostly exists as a visual cue that the intersection follows roundabout rules.
Ok, I was working under the impression that one must drive around the circle. If that requirement isn't there and it just changes how we work out who goes when then I can see that expansion wouldn't be necessary.
The north and south exits to the roundabout are 10.5m across, including the traffic islands; the west exit is 5m across. The 4-way junction you've linked to, the exits are 9.5-11 meters across.
That intersection you showed is clearly big enough. This one doesn't look big enough. Or is it? There are smaller intersections than this one, also. (And I realized that this one might be a bad example because it's not four directions.)
https://goo.gl/maps/fBEysywZgdQVWH7N9