Well, I have no clue how to make a wither farm, and never will, but I like the idea because it has the possibility to expand the wither skull market, making beacons cheaper, as well as the cobble/stone and wood markets.
If the prices work out on this so that there's little/no loss or a profit, then production is not worth discussing in this thread. Maybe someone should have a talk about shutting down 7-wither farms, though. People can already build these and negate all/most rupees lost to despawning. This means that letting us name tag the wither doesn't really affect the production, other than adding a few seconds to spawn the wither each time you show up at your farm. What are the current reasons name tags aren't allowed to be used?
Yeah, this is mind-blowing, also wood economy blowing (if it was possible on emc). For non-afk farms im using this one : You just tp to the y=100, fall on tree and spent 95% of time chopping wood ^^ (thanks to EMC RTS system). Filling DC in like 3+ 1+ (measured) hour.
Logic Error Detected. Correction in progress ... Name tags work just fine on passive critters. If you want to name chickens, cats, dogs, sheep, etc, go right ahead (though I find renaming the egg is more efficient in most cases). Their function is intact. Hostile mobs simply refuse to submit to your attempts at domestication. Personally I'd love a pet cave spider to follow me around, but I would never support making anything hostile immune to despawning - especially not something as devastatingly destructive as a Wither. Imagine for a moment, logging in to your wilderness outpost and finding someone left a renamed Wither to greet you. Quickly followed by death, and a landscape of craters that would make a hive of Creepers envious. As was already said, there's just too many ways this could be abused.