First of all, we need to understand that conditional statement should have been express an idea that is not real. For some reason or another, it did not happen.
When we use the phrase should have, it implies, in a stronger sense, that something is SUPPOSED to happen but didn't. It mostly takes the form of an obligation. For example: We should have been more careful. You should have been upfront about your intentions.
In the case of the statement "I am so biased to what we should have been". The confusion lies on the usage of the conditional phrase because the statement implies a possibility. Hence, I think the more appropriate conditional phrase to use would be "could have been". When using this phrase, it implies that you have the CAPABILITY of doing something in the past or that something could have possibly happened had the conditions been met.
If you can provide the context of this statement, then we may be able to better analyze what the writer is trying to imply.