The universe is weird sometimes. See, The War Z is not - nor, based on development time, could it be - entirely a Day Z clone. Yes, it's an MMO with (optional) permadeath set in a "post-apocalyptic, zombie-infested world where other players can prove to be a greater threat than the undead hordes that populate the land," but it began development last year and is set to launch this fall. So while I imagine there's some inspiration, it seems to have overlapped with one of those strange situations where a bunch of people in different parts of the world had many of the same ideas at once. And, encouragingly, The War Z looks to set itself apart with a very strong Fallout-ish RPG streak as well.
While there's certainly a sandbox element to The War Z, it sounds like a lot more of, well, a game than Day Z's current mutation. Yes, all the zombie apocalypse staples - gathering food and supplies, setting traps, mistrusting other people - are definitely in place, but there's a far more concrete framework holding the whole thing in place. For example, it'll "allow players to earn experience points and then spend those points to learn new skills that will aid in their survival." Also, there'll be a tangible in-game currency and designated "safe settlements" that basically function as social hubs.
An interview with IGN, meanwhile, gives a clearer idea of The War Z's structure, which sounds like an MMO (think: quests) that's been bitten by a more-radioactive-than-usual copy of Fallout 3. Here's the most promising bit:
"While exploring the world, scavenging for supplies, weapons, ammo and gear, players will be able to find notes and diaries - text pieces left by other players or NPCs. For example, you can find a diary that tells the story of a family escaping their home and running from zombies - and dying one by one. If you read carefully you can find clues that will point you to a place where you can find better equipment. Another scenario would be finding a note from another real player - this note could either help you or lure you into a trap - you never know what other players intentions are."
As for permadeath, it's certainly a big part of The War Z, but it's far from the only way to play. A less punishing "normal" mode, Hammerpoint explained, will merely incapacitate a character who's bitten the big one or been bitten by a big one for a fairly lengthy (by MMO standards) period of "between 24 to 48 hours." Meanwhile, the option to play on different sorts of servers - public or private - should keep that from causing a massive balance issue.
So, while I have my doubts about how some of the more traditional MMO elements will mix with Day-Z-style survivalism rivalism, The War Z sounds like it could make for an accessible, potentially more robust alternative. If you feel so inclined, you can sign up for the beta - which will kick off in "the near future" - right now.