The justification for getting rid of the link to the Download page under "Get MediaWiki" is that it's already linked from Main Page, which is a point that also covers half the side bar (e.g. the user manual, the communications page, etc.).
This page is the main page newbies on the wiki will want to go after landing on a neat feature they've seen and want to try out, e.g. Extension:DiscussionTools or Extension:VisualEditor. I think it merits being retained on every page.
It also has the most pageviews by a significant margin, though I'm not sure why that is.
Looking at the original thread, I see @AKlapper (WMF) had originally suggested:
Rename "Get MediaWiki" to "Install MediaWiki" and link to Manual:Installing MediaWiki instead which covers all steps (including downloading and additional extensions).
and the entry was removed entirely in the later proposal (as copied to this project page).
I'm uncertain about all 3 options, namely:
IMHO remove entirely as this activity is prominently covered on the front page. I don't think I'd often end up on some random page and after reading it think "Oh, and now I really want to get/install MediaWiki!" which would justify having this always exposed...
Can you give some data to support your implicit supposition that people who come to the wiki without full plans / experience generally start from the Main Page? This feels a very unlikely outcome; I understood that most of our incoming traffic is from search engines.
@Jdforrester (WMF) That is not my implicit supposition. Every page is page 1. People can reach the main starting page with the most important links to start with with one click in the side bar. If I get you correctly, do you imply that we should have all items which are currently on the main page also duplicated in the side bar?
No. I'm saying that the most important link on the entire wiki is "Get MediaWiki", not the front page that people will generally ignore by default as it's the place websites put their marketing. Obviously I do not think we should have "all" items, but we should have the more important ones ahead of the ones that are less so.
While I don't think that most people need to download and install MediaWiki every time they visit this website...