If so, what are the support values needed for maximizing those values?

I think a healthy dose of moral uncertainty (and normative uncertainty in general) is really important to have, because it seems pretty easy for any ethical/social movement to become fanatical or to incur a radical element, and end up doing damage to itself, its members, or society at large. ("The road to hell is paved with good intentions" and all that.)

A large part of what I found attractive about EA is that its leaders emphasize normative uncertainty so much in their writings (starting with Nick Bostrom back in 2009), but perhaps it's not "proselytized" as much as it should be day-to-day.

At its heart, EA seems to naturally tend to promote a few things:

• a larger moral circle is better than a smaller one
• considered reasoning ("rationality") is better than doing things for other reasons alone
• efficiency in generating outcomes is better than being less efficient, even if it means less appealing at an emotional level

I don't know that any of this are what EA should promote, and I'm not sure there's anyone who can unilaterally make the decision of what is normative for EA, so instead I offer these as the norms I think EA is currently promoting in fact, regardless of what anyone thinks EA should be promoting.

Not exactly answering your question, but I think EA has really good communication norms--such as steelmanning your opponent, focusing on empiricism, open discussion, double crux, no persona attacks, etc.

I do think the broader society can benefit significantly in discussing thorny topics (i.e. politics) if they adopted these communication norms.

This is an interesting question. 

One possible value is something like intrinsically valuing Truth or Better Reasoning. Perhaps also something like Productivity/Maximisation. The rationality community is perhaps a good example of promoting such values (explicitly here). 

It feels somewhat double-edged to promote instrumental values. This can cause all types of troubles if it's misinterpreted or too successful.

What do you think are the important values? 

My interpretation of this was promoting robustly good values (e.g. violence is bad) at scale as an effective intervention.

For instance, these are values that the UK government tries to promote:

"Champion democracy, human rights and the rule of law, and address global challenges, including through campaigns on preventing sexual violence in conflict, reducing modern slavery and promoting female education. Promote human and environmental security through London Illegal Wildlife Trade Conference. Deepen relationships between states and people, including through the Commonwealth Summit."

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/827788/FCOAnnualReport201819.pdf#page=32