Should surname/last name WP:PRIMARYREDIRECTs (examples, Einstein, Byron, Freud) be deprecated? --

Editorial principles

1. The first mention of a person should be wikilinked to the article about them. Later mentions often don't need to be linked (MOS:REPEATLINK)
2. The first mention of a person should make use of their full name (ie <First name> <Last name>, or commonly-used name). Later mentions then use only the last name, for brevity (MOS:SURNAME)
3. Most biographical articles have titles in the form <First name> <Last name>, or are some other commonly-used name (WP:NCPEOPLE, disambiguation aside).

I believe these principles have generally strong support. Taken together, we reach this conclusion:

The first mention of a person should use their full name (<First name> <Last name>, or commonly-used name), based on the title of the article about them and wikilinked to it. Subsequent mentions should use their surname only and not be wikilinked.

In other words, there should be almost no editorial use case for surname WP:PRIMARYREDIRECTs if editors are following good practices.

Searching

One argument is that surname WP:PRIMARYREDIRECTs aid with searching. This is only true for people that use the internal search box and does not apply to the vast majority of readers who visit by using external search engines, which deliver them directly to the right article, ignoring any redirects. The absence of surname redirects will perhaps inconvenience some (slightly, by adding an additional click of a link that will likely be at the top of the WP:DABPAGE or WP:NAMELIST anyway), but removal will actually aid everyone else who is searching for other content using that term because they will be taken directly to a DABPAGE or NAMELIST . This is the exact same scenario as keeping these redirects (searchers of other topics now have to click a hatnote link to a DABPAGE or NAMELIST) - no matter which direction we go, some internal searchers will be inconvenienced by an extra click, and so this issue is a stalemate and should be minimized from consideration.

Case study

In preparing this, I took the quintessential WP:PRIMARYREDIRECT example of Einstein and reviewed how it was being used. I found 334 links to Einstein and ran through them. I replaced first mentions with <First name> <Last name> (linked using simply [[Albert Einstein]]) and removed any repetitious links. On first pass, ~272 full name/wikilink replacements were made per the Principles above, and ~19 inappropriate links were fixed (Einstein family, Einstein (horse), etc.) for a total of 291 (~87% of total) which misused "Einstein". The 43 remaining uses of "Einstein" links were first mentions of Einstein and were found inside quotes or titles. These 43 could (should) be replaced by [[Albert Einstein|Einstein]] so that when users hover over the link they see the full name and true destination of the link.

Conclusion

Surname WP:PRIMARYREDIRECTs should be deprecated because they promote bad editorial practice related to mentions of people. This would not affect other non-biographical uses of WP:PRIMARYREDIRECTs, because this issue is specific to how we handle mentions of personal names in articles. --