The horrid lag in Crucible will persist until Bungie moves away from using geolocation as a major filter for CBMM.

It became very obvious to me based on who I was being matched with that Destiny was CBMMing me (in both the Crucible and PvE/Tower) as if I lived in Hawaii, when I live in San Diego.. the two are very far apart and Hawaii's relatively limited networking to the rest of the world makes things even worse than just the distance problem.

The reason they kept matching me with Hawaiians is almost certainly that they use a geolocation database provider as a first pass filter for matchmaking, because I know a couple of the major ones list the IP C Block addresses that Time Warner assigns me to as being in Hawaii when they aren't (I've reported this to the providers, but they are very slow to update any changes.. months/years).

A lot of geolocation data these providers keep is wildly inaccurate despite what the providers promise (look at https://www.iplocation.net/ to see where geolocation providers think you are, for some people it will be roughly accurate for their ISPs, for others it will be literally across the country or in some cases, the wrong country or continent completely).

I kinda-sorta solved the Hawaii issue by buying a small OpenWrt router to place between my console and my real router and VPN through that using a low-latency VPN provider with exits in Los Angeles and other California cities, but it is somewhat ridiculous that I have to work around the problem on my end, and while this improved my Crucible experience noticeably, things are still wonky because so many other people are getting bad CBMM matches because of bad geolocation data.