Tbh, I’m not really seeing any contradictions. The game already has a system for determining who goes into which Bracket when a Guild doesn’t register and then returns, and I’m not suggesting any changes to that. Each Guild is given a ranking after each GW, and I imagine (I don’t know for sure/exactly how it works) they’re just slotted back in at that ranking if they’ve sat out any wars, with Brackets adjusted accordingly. After all, if all the Guilds below got to move up one place for the next GW, having them (or the newly-ranked Guilds in those positions) move back down one place once the returning Guild is slotted in makes sense.
The idea is that the Guilds below get a chance to play in a higher Bracket, get (potentially and marginally) better rewards and then potentially move up more easily than would otherwise have been possible. If the De-registering Guild comes back and is an active competitor in their Bracket, I don’t see that as a bad thing or undeserved. Realistically, if they come back and score poorly, I’d like to see them drop down appropriately. If one of the other Guilds moves up above that ‘preserved’ ranking, they wouldn’t be affected by the re-insertion, either, meaning they’ve had an easier time moving up than if there was an additional Guild clogging up the works there that they had to climb over. I hope that makes it a little bit clear why I don’t think it’s a contradiction and that it does actually make a difference, particularly if it’s more than just one guild.
It’s also possible (not something I’ve tested or watched for, and may be old) that an unregistered guild will still fall down Brackets anyway:
In that case, the question becomes irrelevant (as the ranking wouldn’t be ‘preserved’). The fact that joining and getting 0 is encouraged is a whole other issue…