I often run London on Gold with no issues at all. This is even when I'm the only sane person taking advantage of higher ground while my party borks around in the kill zone. As long as I watch my corners and stay near cover, then I'm fine.
I don't mind the center hack zone because, while it is challenging, there is still a lot of cover around that can be taken advantage of. Good use of that area depends more on having a good team that is willing to hunker down and watch their own AOR, plus an ability to jump between cover as the tactical situation changes.
In short: London isn't that bad to me. There are other maps I find to be far more annoying.