This might be a little bit stalker-y, but I think the name change might have been pushed by a major investor in Warlight/Warzone:
I have consulted on several huge projects which I am allowed to talk about over the last 10 years, names like Phone.com, Beer.com, and Software.com that sold for millions. I have also helped acquire several domains for start-up companies that were rather cheap but quality (IPractice.com, Warzone.com, Estately.com, RobotLab.com, and DealPop.com). Those companies have gone on to do well because they have a good domain. A great domain name can be a useful tool to becoming a successful business.
- Jay Westerdal, http://www.gotdomain.com/
(this appears to be from well before the actual Warzone switch)
This is also the agent Warzone.com, LLC, is registered under. And if you follow the address on that registration (or on the Android app) it takes you to what I think is this investor's house. Given that the house is located on Mercer Way, on Mercer Island, and zoned to Mercer Island High School, I think it's also to safe to say that this person is Mercer. Mercer was I think at some time suggested on livestream to be the person who came up with and pushed the Warzone rename.
So my best guess is that Fizzer/Mercer see a lot of upside in the Warzone name/brand + the Warzone domain in the long term. Although ironically enough it looks like warzone.feedback (Westerdal seems to be heavily invested in the .feedback TLD) got taken up by some other Warzone, and there's a lot of other Warzones to compete with. Warzone.com isn't anywhere close to the top of Google results just yet, but that's probably because of how recent the switch is. Fizzer also mentioned that Warlight referred to Silverlight, and Silverlight has been on the verge of death for some years now (Warlight doesn't use it anymore either from what I can tell). My guess is that:
a) Westerdal seems to be a big believer in having the right name/domain for your brand
b) "warzone" is a more common word than "warlight," which is an outdated portmanteau anyway
c) if Warzone/Warlight manage to take over warzone.com and outmaneuver all the other Warzones, they've got a better domain/name to work with to reach new people
While this is all public information that there appear to be no attempts to conceal, and while Westerdal is a fairly well-known and successful entrepreneur/investor who seems to be passionate about Warlight/Warzone, I don't know if this is a little bit too creepy on my part. Will take this down upon request if someone thinks it's too much investigating. Also keep in mind that a lot of the stuff above might be incorrect inferences on my part.
Edited 11/14/2017 19:08:15