How to find the leading researchers in a new field
Problem is that you hamstrung yourself by eliminating the only correct strategy: doing a long literature survey yourself. You wish to rely on proxies, and sometimes surveys can do that for you, but other people's opinions of "good" and "bad" are just that: opinions.

The only way to really get a sense of good and bad is to read a LOT, think a lot about what you read, discuss with people who might know more about the area, think a lot more, read more, and repeat.