Nuts. The 1m size limit is a little painful. I had a large statute build that was originally green-lit by Tibbers for transfer, but if air space is included in the block count then it doesn't fit, since most of it is hollow. I'm guessing there's nothing I can do about that other than play with the coords and just take half of it? You did say non negotiable...
That being said, I do agree a clean slate is for the best. I'm not the oldest player but I've been here since the end of 1.7. I've gone through everything from the ridiculous resource holes, the ownership transfer from PonyMC to PArc, the 2 weeks when we tried out economy and removed it, and just about everything else in between. I don't mind losing my massive stockpile of stuff because I've never even gotten around to touching them anyways. What I'll miss is the silly mod items, the stuff from old events, because they hold some good memories.
I like the idea of new map generation, if it ends up being feasible. More dungeons and stuff will be super cool. I'd love to see randomly generated dungeons that's more than the vanilla "one room with a spawner and 2 chests".
Dungeon world sounds ridiculously fun. Is it hand crafted? It sounds like you guys are building it block by block or something. I do wonder if it'll be reset periodically or if there's endless number of dungeons through procedural generation. Otherwise early players end up looting everything leaving nothing for future players, which is a problem I've noticed in many other popular heavily-modded servers.
tl;dr words and good times.