I'm not sure how this map has maintained it's popularity, but regardless I have plans to update and and revamp Washington Large.

This version of WL will be repaired and maintained to be playable on the newest version of Unturned, however no new content will be added and any quirks of the map's design will be left just as they were back in 2016. This will become the "Archive" version of Washington Large / Washington II

A second "revamped" version of WL called Washington II will be released later on that will fix a lot of the complaints and issues of the original. Note though this will be missing some features such as NPC's as I already have a map planned for the near future that will address this and much more.

TLDR: Washington Large is getting an update, and a revamped version (Washington II) is in the works.

UPDATE: This is on hold until things in my personal life improve, sorry for the possible disappointment.