This has not been resolved. It was open since long, kept voluntarily opened, but nothing has changed since my new comment, related to the fact that there's now no longer any distinction between HTTP and HTTPS. Before there was a distinctive padlock, it has been removed for the standard blue icon for both and in all cases. However this means we equate HTTP and HTTPS in all situations, including when we are currently browsing the wiki in HTTPS and click to an external HTTP (which means reduced security).
The icon may remain the same blue icon when browsing the wiki in HTTP only (HTTP to HTTP does not reduce the security, and there's still no need for the padlock when going from HTTP to HTTPS or from HTTP to HTTPS).
But we must preserve the users' privacy as much as possible **BEFORE** they ever try to click a link to a non-authenticated site (possibly hacked or derouted) that this navigation may be unsafe (users browsing the wiki from HTTP are already unsafe, there's nothing we can do for them that will further reduce their security and privacy).
It is still a major goal of Wikimedia to use HTTPS, and Wikimedia has multiple times reaffirmed its strong supprot for HTTPS, exactly as a preventive measure to help its own users keeping their pricacy when they navigate the wikis via HTTPS (and we have convinced them to do that, not just for logging in, but throughout their navigation on the wiki, but also because it can help prevent some attacks on their visit by various cross site scripting technics or some malwares in their browser plugins: browsers do not correctly isolate plugins that can easily interact with unsecured HTTP sites but have much more troubles doing it when visiting an HTTPS site, where the browser's sandboxing is far more efficient). But HTTPS is definitely protecting them better from monitoring by third parties by some intermediate proxies: their navigation on the wiki remains private (only edits made by them are public, but under only via their wiki account pseudonym, and proxies cannot monitor completely what they have modified or changed in their private user data or preferences and their session cannot be silently injected some spying code inserted by proxies or altered silently).
So yes I'd like to see distinctive icons when navigating wikis with HTTPS, and clicking to an external unsecure site, which may have been hacked, or changed to become malicious, or whose domain expired and was cybersquatted by malwares: this has already happened in Wikimedia wikis, where external unsecured sites where initially safe, but came down or were hacked by unknown black hat parties.
We don't need to alert anyone if all allowed external sites are HTTPS, we can assume that because the external site was already evaluated, its identity was verified and is still liable if something goes wrong and their HTTPS certificate is still valid. There are now too many sites on the web that get hacked massively.
We need some prevention and education of users, informing them preventively BEFORE they follow the link which was evaluated only in some past. We cannot count only on the presence of the padlock in browser's adress bar, because it is already TOOL LATE: privacy has already been breached, and security already compromized (and not everyone will see it, the site may have been hacked for specific ranges of users by attacks on specific routers and we will never be able to detect that if these routers have no public access from elsewhere). That's exactly what HTTPS helps preventing. If we follow any HTTP link from a HTTPS wiki, it's too late for that user, his privacy or security may already have been breached, before the user sees the padlock on their browser bar.