Ensuring high quality sources where needed, especially science/academic topics (narrow focus)

The senior editor idea could work. Wikipedia is not supposed to be elitist or restrictive, but it IS a meritocracy in the sense that good edits are more likely to survive the bad ones (and the same with good editors). There might be objections to putting hard limits on user activity. But it is much more desirable to ask editors to "prove" and "earn" their merit, and certain privileges that come with it.

I think the workshop is a decent idea for a senior editor. But it depends on what privileges we're giving to senior editors. If we're actually entrusting them with certain tools, or giving them a little more weight in certain situations, then they need to actually have a track record of action. It's one thing to take a workshop on what you're supposed to do. It's another thing to actually do it.